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Fractional Dosing Study in Brazil

Fiocruz, the Brazilian public health institute, will test half doses of the AstraZeneca vaccine. Not much information available yet. From a Google Translate article.

BANDNews: Fiocruz, in partnership with the government of Espírito Santo, is going to carry out a study with the application of half a dose of the Astrazeneca vaccine to the entire population of the municipality of Viana, in Greater Vitória.

The city has about 35 thousand inhabitants.

The immunization will take place on Sunday, June 13, and residents will be able to choose whether they want to participate in the study.

According to the state secretary of Health, Nésio Fernandes, there is already evidence of the effectiveness of the application of half a dose of the vaccine in immunization against Covid-19.

If the experience is successful, it will be possible to double the number of people vaccinated in the country with the immunizing agent produced by Fiocruz.

See my previous posts on fractional dosing for why this is very important.

Hat tip: Cisco Costa.

Fractional Dosing Trials Now!

Fractional dosing has the potential to massively increase the supply of COVID vaccine. The Moderna Phase I clinical trial and Pfizer Phase I/II trials already indicated a substantial immune response with smaller doses but the vaccine companies are under-incentivized to run additional fractional dosing trials (they won’t gain trillions, at best they will gains billions and might even lose some profit) and governments and private organizations are not picking up the ball. There are just two small trials underway that I am aware of:

N.B. now that we know that the vaccines work. we don’t need to study every dosage for efficacy against the virus. Instead of efficacy studies we can study how the vaccine is working in the body compared to those fully immunized, immunogencity trials (which is what the above trials are doing) and then use data and theory to infer effectiveness. If we felt it necessary to study effectiveness, human challenge trials would be ideal in this situation as you can study gradually smaller doses with little risk to the patients. But given the urgency, immunogenicity trials should provide enough information to make decisions on the ground. To limit risk, one could do a half-dose on the second dose or one could do a half-dose in people under the age of 50. Both of these regimens would still create significant increases in supply. Recall that in 2018, facing a yellow fever epidemic and a shortage of vaccine, Brazil used 1/5th doses to break the epidemic.

There are no guarantees but the world is ignoring a potential trillion dollar bill lying on the sidewalk.

Hat tip for discussion: Witold and Amrita.

India Delays the 2nd Dose; Delaying 2nd Dose Improves Immune Response; Fractional Dosing

India has delayed the second dose to 12-16 weeks.

In other news, delaying the second dose of the Pfizer vaccine appears to improves the immune response (as was also found for the AstraZeneca vaccine). The latter is a news report based on a press release so some caution is warranted but frankly this was always the Bayesian bet since most vaccines have a longer time between doses as that helps the immune system. As Tyler and myself both argued, the short gap between the first and second dose was chosen to speed up the clinical trials not to maximize immunity. That was the right decision in the emergency but it was never the case that following the clinical trial regimen was “going by the science” no matter what Fauci said.

Many lives have been lost by not going to first doses first earlier, both here and in India.

Every country should move to a regimen in which the second dose comes at 12-16 weeks, even the United States, as this may improve the immune response and help other countries get a little bit ahead in their vaccine drives.

May I now also beat the drum some more on fractional dosing? Many people (not everyone) report that the second mRNA dose packs a wallop. I suspect that a half dose at 12-16 weeks would be plenty and that would free up significant capacity to vaccinate more people with first doses. We could also run some trials on half-doses for the young as a way to balance dosing and risk. Again this will matter for the rest of the world more than the United States but stretching doses in the United States will help the rest of the world and the arguments against stretching doses are now much diminished.

A Half Dose of Moderna is More Effective Than a Full Dose of AstraZeneca

Today we are releasing a new paper on dose-stretching, co-authored by Witold Wiecek, Amrita Ahuja, Michael Kremer, Alexandre Simoes Gomes, Christopher M. Snyder, Brandon Joel Tan and myself.

The paper makes three big points. First, Khoury et al (2021) just published a paper in Nature which shows that “Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection.” What that means is that there is a strong relationship between immunogenicity data that we can easily measure with a blood test and the efficacy rate that it takes hundreds of millions of dollars and many months of time to measure in a clinical trial. Thus, future vaccines may not have to go through lengthy clinical trials (which may even be made impossible as infections rates decline) but can instead rely on these correlates of immunity.

Here is where fractional dosing comes in. We supplement the key figure from Khoury et al.’s paper to show that fractional doses of the Moderna and Pfizer vaccines have neutralizing antibody levels (as measured in the early phase I and phase II trials) that look to be on par with those of many approved vaccines. Indeed, a one-half or one-quarter dose of the Moderna or Pfizer vaccine is predicted to be more effective than the standard dose of some of the other vaccines like the AstraZeneca, J&J or Sinopharm vaccines, assuming the same relationship as in Khoury et al. holds. The point is not that these other vaccines aren’t good–they are great! The point is that by using fractional dosing we could rapidly and safely expand the number of effective doses of the Moderna and Pfizer vaccines.

Second, we embed fractional doses and other policies such as first doses first in a SIER model and we show that even if efficacy rates for fractional doses are considerably lower, dose-stretching policies are still likely to reduce infections and deaths (assuming we can expand vaccinations fast enough to take advantage of the greater supply, which is well within the vaccination frontier). For example, a half-dose strategy reduces infections and deaths under a variety of different epidemic scenarios as long as the efficacy rate is 70% or greater.

Third, we show that under plausible scenarios it is better to start vaccination with a less efficacious vaccine than to wait for a more efficacious vaccine. Thus, Great Britain and Canada’s policies of starting First Doses first with the AstraZeneca vaccine and then moving to second doses, perhaps with the Moderna or Pfizer vaccines is a good strategy.

It is possible that new variants will reduce the efficacy rate of all vaccines indeed that is almost inevitable but that doesn’t mean that fractional dosing isn’t optimal nor that we shouldn’t adopt these policies now. What it means is that we should be testing and then adapting our strategy in light of new events like a battlefield commander. We might, for example, use fractional dosing in the young or for the second shot and reserve full doses for the elderly.

One more point worth mentioning. Dose stretching policies everywhere are especially beneficial for less-developed countries, many of which are at the back of the vaccine queue. If dose-stretching cuts the time to be vaccinated in half, for example, then that may mean cutting the time to be vaccinated from two months to one month in a developed country but cutting it from two years to one year in a country that is currently at the back of the queue.

Read the whole thing.

The Becker-Friedman center also has a video discussion featuring my co-authors, Nobel prize winner Michael Kremer and the very excellent Witold Wiecek.

Two Vaccine Updates

First, in an article on new vaccine boosters in USA today there is this revealing statement:

Any revised Moderna vaccine would include a lower dose than the original, Moore said. The company went with a high dose in its initial vaccine to guarantee effectiveness, but she said the company is confident the dose can come down, reducing side effects without compromising protection.

Arrgh! Why wait for a new vaccine??? Fractional dosing now!

A microneedle patch for vaccines.

The same article also notes:

One of Moderna’s co-founders, MIT professor Robert Langer, is known for his research on microneedles, tiny Band-Aid-like patches that can deliver medications without the pain of a shot. Moderna has said nothing about delivery plans, but it’s conceivable the company might try to combine the two technologies to provide a booster that doesn’t require an injection.

The skin is highly immunologically active so you can give lower doses with a microneedle patch. The microneedles are sometimes made from sugar and don’t hurt. Microneedle delivery, however, can cause scars but I say apply the patch where the sun don’t shine and let’s go!

Second, Canada’s NACI has now endorsed mix and match for the AZ and Pfizer and Moderna vaccines. First Doses First has put Canada in very good shape (now ahead of the US in percent of the population with at least one dose) and this was always part of the FDF plan–delay second doses to get out more first doses and then, when supplies increase, give second doses, possibly with a better vaccine.

Cold Storage No Longer a Constraint

Yahoo: With little fanfare, the U.S. Food and Drug Administration gave Pfizer permission this week to store its COVID-19 vaccine in a typical refrigerator for one month — freeing the vaccine from the need to be shipped in cumbersome boxes stuffed with dry ice.

Among authorized COVID-19 vaccines, Pfizer’s vaccine was notorious for its ultra-cold storage requirements. Now, as the only vaccine authorized for children ages 12 to 17, this new flexibility could dramatically accelerate the effort to vaccinate America’s teens and adolescents.

Pfizer spent millions on its cold storage technology and now discovers that it isn’t strictly necessary–that wasn’t a mistake, Pfizer did the right thing–but it’s a good reminder of how new this technology is and also how the clinical trial decisions are not written in stone.

Straussian take: Investigate fractional dosing.

India’s Pandemic and the World

Shruti Rajagopalan is right, helping India isn’t just about India.

India’s role in the global pandemic is unique. The developing world is counting on affordable Indian vaccine-makers such as Serum Institute of India Pvt. Ltd. for their supplies. With India now reserving virtually all its doses for domestic use, those countries will have to wait even longer to be vaccinated. And if the pandemic disrupts production at Indian pharmaceutical companies, it could affect crucial non-Covid medications as well. Half the world’s children have been vaccinated by Serum Institute.

The Biden administration can do two things to help. The first is to ease restrictions on critical exports, imposed under the Defense Production Act to prioritize the needs of U.S. companies.

Vaccine production requires very specific, medically approved inputs, which are difficult to substitute quickly in the middle of a pandemic. Currently, U.S. producers must secure permission before exporting such things as special sterile filters, disposable bags for cell cultures, cell culture media and single-use tubing. The embargo has led to major bottlenecks. Serum Institute says that without those inputs, it may not be able to deliver the 160 million vaccine doses it had planned to produce next month.

Second, the U.S. should immediately share doses from its own supply of Oxford-AstraZeneca and Johnson & Johnson vaccines.

I have three things to add. First, I have already noted the foreign policy implications which weigh strongly in favor of taking a more active role in the world pandemic.

Second, India should move immediately to delay the second dose of the AZ vaccine to 12 weeks. The federal government has already recommended a 6-8 week schedule, as this improves efficiency of the AstraZeneca (Covishield) vaccine, but many people so fear shortages that they are getting a less-effective second dose at four weeks. An enforced 12 week schedule would improve efficiency and might also reassure people that there will be supplies in 12 weeks.

Third, and this is more speculative, but the rising pandemic in India provides an opportunity to test fractional dosing of the Pfizer and Moderna vaccines in a real world setting. There is currently a small-scale Belgian trial testing Moderna at 50 mcg and Pfizer at 20 mcg. We already have reasonable information that 50 mcg of Moderna induces a robust immune response in adults. The mRNA vaccines wouldn’t work in all of India but would be fine in the cities and perhaps there is an opportunity for an exchange similar to what Israel promised to get early supplies.

My Congressional Testimony

I thought the meeting went well. I made four points.

  • It is not too late to do more.
  • We should invest in nasal and oral vaccines.
  • We should vaccinate the world.
  • We should stretch doses through fractional dosing and delaying the second dose, this will be important to vaccinate the world quickly.

One observation. Lots of people are talking about vaccine hesitancy but I am one of the few people who have been talking about nasal and oral vaccines which are the only really solid approach to the issue that I have seen.

My best line:

The unvaccinated are the biggest risk for generating mutations and new variants. You have heard of the South Africa and Brazilian variants, well the best way to protect your constituents from these and other variants is to vaccinate South Africans and Brazilians.

I also got in the last word in Q&A when discussing the pause of J&J:

For the rest of the world it is important to underline that it is most important to get vaccinated now. Use the AstraZeneca vaccine, use the Johnnson & Johnson vaccine…don’t wait for Moderna or Pfizer, it is going to take too long…start your vaccination program early…vaccinate as quickly as possible, that is the route to health and wealth.

See Western Warnings Tarnish Vaccines the World Badly Needs for the beginnings of a disaster. Note that if J&J and AZ are tarnished or knocked out of the vaccine arsenal then dose stretching and investing in more capacity are going to be even more important.

I also submitted five excellent and important pieces to Congress:

Canadian statement on delaying the second dose.

National Advisory Committee on Immunization (NACI) Canada. 2021. “COVID-19 Vaccine Extended Dose Interval for Canadians: NACI Recommendation.” Government of Canada. March 3, 2021. https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/rapid-response-extended-dose-intervals-covid-19-vaccines-early-rollout-population-protection.html.

Value of vaccine capacity and additional investments.

Castillo, Juan Camilo, Amrita Ahuja, Susan Athey, Arthur Baker, Eric Budish, Tasneem Chipty, Rachel Glennerster, et al. 2021. “Market Design to Accelerate COVID-19 Vaccine Supply.” Science, February. https://doi.org/10.1126/science.abg0889.

Efficacy of the first dose from NEJM.

Skowronski, Danuta, and Gaston Serres De. 2021. “Letter to the Editor on Safety and Efficacy of the BNT162b2 MRNA Covid-19 Vaccine.” New England Journal of Medicine, February 17, 2021. https://doi.org/10.1056/NEJMc2036242.

Overview of dose stretching policies (with links in the online version).

Tabarrok, Alex. 2021. “What Are We Waiting For?” Washington Post, February 12, 2021, sec. Outlook. https://www.washingtonpost.com/outlook/2021/02/12/first-doses-vaccine-rules-fda/

A plan to vaccinate the world.

Agarwal, Ruchir, and Tristan Reed. 2021. “How to End the COVID-19 Pandemic by March 2022” SSRN. 2021. https://documents.worldbank.org/en/publication/documents-reports/documentdetail/181611618494084337/how-to-end-the-covid-19-pandemic-by-march-2022

The whole thing is here. My written testimony is here.

Atul Gawande and Zeke Emanuel Now Support Delaying the Second Dose

Many people are coming around to First Doses First, i.e delaying the second dose to ~12 weeks. Atul Gawande, for example, tweeted:

As cases and hospitalizations rise again, we can’t count on behavior alone reversing this course. Therefore, it’s time for the Biden admin to delay 2nd vax doses to 12 weeks. Getting as many people as possible a vax dose is now urgent.

Now urgent??? Yes, I am a little frustrated because the trajectory on the new variants was very clear. On January 1, for example, I wrote about The New Strain and the Need for Speed (riffing off an excellent piece by Zeynep Tufekci).  Still, very happy to have Gawande’s voice added to the cause. Also joining Gawande are the power trio of Govind Persad, William F. Parker and Ezekiel J. Emanuel who in an important op-ed write:

If we temporarily delay second doses …that is our best hope of quelling the fourth wave ignited by the B.1.1.7 variant. Because we did not start this strategy earlier, it is probably too late for Michigan, New York, New Jersey and the other Northeastern states. But it might be just in time for the South and California — the next places the more infectious strain will go if historical patterns repeat.

…Drug manufacturers selected the three- or four-week interval currently used between doses to rapidly prove efficacy in clinical trials. They did not choose such short intervals based on the optimal way of using the vaccines to quell a pandemic. While a three- or four-week follow-up is safe and effective, there is no evidence it optimizes either individual benefit or population protection.

…Some complain that postponing second doses is not “following the science.” But the scientific evidence goes far beyond what was shown in the original efficacy trials. Data from the United Kingdom, Israel and now the Centers for Disease Control and Prevention shows that first doses both prevent infection and reduce transmission. In people with prior infection, experts are beginning to recognize that a second dose could provide even less benefit. Following the science means updating policies to recognize new evidence rather than stubbornly maintaining the status quo.

Emanuel is on Biden’s COVID-19 task force so consider this op-ed running the flag up the flagpole. I predict Topol will fall next.

I would be surprised, however, if the US changes course now–too many people would then ask why didn’t we do this sooner?–but dose stretching is going to be important for the rest of the world. Why aren’t we doing more to investigate fractional dosing? Even if we went to half-doses on the second dose–the full second dose appears to be strong–that would still be a significant increase in total supply.

Addendum: I have argued for sending extra doses to Michigan and other hot spots such as NJ. Flood the zone! The Biden administration says no. Why? Production is now running well ahead of distribution as more than 50 million doses have been delivered but not administered. It would be a particularly good idea to send more single-shot J&J to reach hard to reach communities–one and done.

From the Comments, On FDF

Sure and Tom Meadowcroft have been hitting it out of the ballpark in the comments sections. Two examples.

Sure:

Protocol was made to serve man, not man to serve the protocol.

The reason we have protocols is because we need to weight the harms of waiting without a treatment against the harms that happen if the treatment is counterproductive in some unforeseen manner.

We can, normally, pretty easily measure the benefit side: count up the mortality and morbidity for the illness in question. The risk side is harder so we developed tests and processes to elucidate those: RCTs, literature reviews, regulatory oversight, mandatory waiting periods. At the end of the day though, the whole process is just one giant test to measure the likely harm of a new entity.

So when is a test worth doing? After all I do not order an MRI for every patient even though I could find a lot of early stage cancers that way.

..GSW to the abdomen with crashing bp with minimal response to volume? Straight to the OR. No matter the results of the CT scan they are still getting opened to stop the bleeding.

…So now we look at the vaccine approval process and methods to stretch doses. Pre-test probability that vaccines work? Inordinately high after passing Phase II. Odds that we hit on the precise optimal timing regimen on the first go? Nil.

The likelihood ratios for RCTs and approval mechanisms are powerful. But we are talking thousands of deaths per day. The odds that these tests will remotely alter management decisions is nil. It is malpractice to delay life saving treatment on tests exceedingly unlikely to change management decisions.

And remember the UK is not seeing horrid outcomes for doing this for a while now. A lot of theoretical failure mechanisms are now off the table.

Science is wholly about building a reliable model that accurately predicts future outcomes of current actions. While doing the actual experiment is the gold standard for knowledge acquisition, it is not the only option and in cases like this pandemic is not sufficiently better than past data to merit waiting.

As far as the regulators. I work with some of them directly. They are not overburdened to anywhere near the degree that the frontline clinicians have been hit. When I ask them to explain their cost benefit calculations, they have none. Not I cannot follow them. Not I disagree with them. They have done not an iota of math to justify their course of action.

Sorry, but I believe in evidence based medicine, not eminence based medicine. If you as a regulator cannot explain to me in technical terms the math behind your decision process, even if only back of the envelope, you are not worth putting in charge.

Approve all the vaccines, FDF, fractional dosing trials, and first dose followed by variolation trials should all be done now. It is was [what] the math demands.

Also this from Tom Meadowcroft:

Scientific researchers search for the truth. Medical clinicians use limited data balance cost and benefits in the face of uncertainty to save the most lives.

When searching for the truth, it is important to have high standards of statistical significance, integrity, and patience, because credibility and a reputation for integrity is everything. Every academic knows that a retracted paper or an accusation of playing fast and loose with statistics can be the death knell for a career. As a result it is prudent to be very certain before publishing. Public health officials, particularly those in charge of approving vaccines, dread the possibility that a vaccine that will be given to millions of healthy people, often children, to prevent diseases where death is rare, which could harbor some flaw that causes a hundred avoidable deaths; they seek the highest standards of proof of safety and efficacy before approving such a vaccine.

But a pandemic is not a search for truth, and a COVID vaccine administered in the midst of a pandemic is very different than a measles vaccine administered to 2-year-olds. The pandemic makes these decisions for FDF or for vaccine approvals into clinical decisions, where health professionals should be balancing the certain benefit of reducing the thousands of daily deaths against the uncertain cost of the possibilities of harmful side-effects and uncertain details of efficacy (when does immunity kick in, how long does it last, how valuable is a booster) that additional months of testing and trials would reveal more clearly.

Public health researchers, academics for the most part, lack the ability (and courage) to make the sort of cost/benefit analysis with necessarily limited data that clinical physicians make every day in examination rooms. Any good clinician, faced with the citizenry of a country as their patient, would have opted for FDF, the AZ vaccine, and quite likely reduced doses by the start of the year. Because we are stuck with academics and administrators as our decision makes, unable to see beyond their usual routine of searching for the truth and protecting their reputations, thousands more will die.

The First Dose is Good

WSJ: The Covid-19 vaccine developed by Pfizer Inc. and BioNTech SE generates robust immunity after one dose and can be stored in ordinary freezers instead of at ultracold temperatures, according to new research and data released by the companies.

The findings provide strong arguments in favor of delaying the second dose of the two-shot vaccine, as the U.K. has done . They could also have substantial implications on vaccine policy and distribution around the world, simplifying the logistics of distributing the vaccine.

A single shot of the vaccine is 85% effective in preventing symptomatic disease 15 to 28 days after being administered, according to a peer-reviewed study conducted by the Israeli government-owned Sheba Medical Center and published in the Lancet medical journal. Pfizer and BioNTech recommend that a second dose is administered 21 days after the first.

The finding is a vindication of the approach taken by the U.K. government to delay a second dose by up to 12 weeks so it could use limited supplies to deliver a single dose to more people, and could encourage others to follow suit. Almost one-third of the U.K.’s adult population has now received at least one vaccine shot. Other authorities in parts of Canada and Europe have prioritized an initial shot, hoping they will have enough doses for a booster when needed.

Preliminary data also suggest that the other widely used vaccine in the U.K. developed by AstraZeneca PLC and the University of Oxford could have a substantial effect after a first dose .

The Israeli findings came from the first real-world data about the effect of the vaccine gathered outside of clinical trials in one of the leading nations in immunization against the coronavirus. Israel has given the first shot to 4.2 million people—more than two-thirds of eligible citizens over 16 years old—and a second shot to 2.8 million, according to its health ministry. The country has around 9.3 million citizens.

…”This groundbreaking research supports the British government’s decision to begin inoculating its citizens with a single dose of the vaccine,” said Arnon Afek, Sheba’s deputy director general.

The Israeli study is here. Data from Quebec also show that a single dose is highly effective, 80% or higher (Figure 3) in real world settings.

It’s becoming clearer that delaying the second dose is the right strategy but it was the right strategy back in December when I first started advocating for First Doses First. Waiting for more data isn’t “science,” it’s sometimes an excuse for an unscientific status-quo bias.

Approximately 16 million second doses have been administered in the US. If those doses had been first doses an additional 16 million people would have been protected from dying. Corey White estimates that every 4000 flu vaccinations saves a life which implies 4000 lives would have been saved by going to FDF. COVID, of course, is much deadlier than the flu–ten times as deadly or more going by national death figures (so including transmission and case fatality rate)– so 40,000 deaths is back of the envelope. Let’s do some more back-of-the-envelope calculations. Since Dec. 14, there have been approximately 10 million confirmed cases in the United States and 200,000 deaths. There are 200 million adults in the US so 1/1000 adults has died from COVID, just since Dec. 14. If we use 1/1000 as the risks of a random adult dying from COVID, then an additional 16 million vaccinations would have saved 16,000 lives. But that too is likely to be an underestimate since the people being vaccinated are not a random sample of adults but rather adults with a much higher risk of dying from COVID. Two to four times that number would not be unreasonable so an additional 16 million vaccinations might have avoided 32,000-64,000 deaths. Moreover, an additional 16 million first doses would have reduced transmission. None of these calculations is very good but they give a ballpark.

It is excellent news that the vaccine is stable for some time using ordinary refrigeration. Scott Duke Kominers and I argue that there is lot of unused vaccination capacity at the pharmacies and reducing the cold storage requirement will help to bring that unused capacity online. The announcement is also important for a less well understood reason. If Pfizer is only now learning that ultra-cold storage isn’t necessary then we should be looking much more closely at fractional dosing.

When I said that we should delay the second dose, people would respond with “but the companies say 21 days and 28 days! Listen to the science!”. That’s not scientific thinking but magical thinking. Listening to the science was understanding that the clinical trial regimen was designed at speed with the sole purpose of getting the vaccines approved. The clinical trial was not designed to discover the optimal regimen for public health. Don’t get me wrong. Pfizer and Moderna did the right thing! But it was wrong to think that the public health authorities could simply rely on “the science” as if it were written on stone. Even cold-storage wasn’t written on stone!  Now that the public health authorities know that the clinical trial regimen isn’t written in stone they should be more willing to consider policies such as delaying the second dose and fractional dosing.

We are nearing the end in the US but delaying the second dose and other dose-stretching policies are going to be important in other countries.

The Big Push: A Plan to Accelerate V-Day

In the Washington Post I have an extensive piece on accelerating progress to V-day, Vaccine or Victory day, the day everyone who wants a vaccine has gotten one. I cover themes that will be familiar to MR readers, including First Doses First, Fractional Dosing, Approving More Vaccines and DePrioritization to Expand Delivery. I won’t belabor these points here but the piece is useful at collecting all the arguments in one place and there are lots of authoritative links.

One point I do want to make is that all the pieces of the “Tabarrok plan,” if  you will, fit together. Namely, use First Doses First to make a big push to get as many people vaccinated with first doses as possible in the next 90 days. Approve more vaccines including Johnson & Johnson, AstraZeneca and others and make them available to anyone, anywhere–that is possible because these vaccines don’t require significant cold storage, J&J is a single shot and AZ is better with a second shot at 12 weeks or later all of which eases distribution.

…some people argue that adding a third (or fourth) vaccine might not help because of persistent delivery logjams at the state and local levels. But we know there is unused distributional capacity, even for the supply we do have. The United States is currently administering about 1.5 million coronavirus vaccine shots per day. While that sounds like a lot, for comparison consider that in September — during the pandemic, when social distancing measures were in full effect — we vaccinated for the seasonal flu in some weeks at the rate of 3 million people a day.

There are two main reasons the rollout has been so slow. First, the Moderna and especially the Pfizer vaccines require ultracold storage. (The Johnson & Johnson and AstraZeneca doses can be stored at ordinary refrigerator temperatures.) Second, we have tried to prioritize vaccinations using a confusing mishmash of age, health conditions and essential-worker status that differs by state and sometimes even by county. “Confirming such criteria is complicated at best, and it’s probably not even feasible to try under conditions of duress,” as Baylor’s Hotez puts it.

Arguments continue about prioritization lists, and the idea of tossing them entirely would cause a political fight. But there is a compromise at hand: Quickly approve the Johnson & Johnson and AstraZeneca vaccines and make them — and only them — available to anyone, anywhere. Keeping things simple is a sure way to increase total vaccinations. With no cold-storage requirement, the new vaccines could be administered by any of the 300,000 pharmacists and more than 1 million physicians in the United States authorized to deliver vaccines, most of whom are not now giving Pfizer or Moderna shots.

No Learning Without Risk

Here’s something from a paper that I am working on. The context is why first doses first makes more sense the greater the uncertainty but the point made is larger. No indent.

An important feature of First Doses First (FDF) and other policies such as fractional dosing is that they are reversible. In other words, FDF contains an option to switch back to Second Doses First (SDF). Options increase in value with uncertainty (Dixit and Pindyck 1994). Thus, contrary to many people’s intuitions, the greater the uncertainty the greater the value of moving to First Doses First. Indeed, the value of the option can be so high that one might want to move to First Doses First even if it were worse in expectation. For example, if the expected efficacy of the first dose were just 45% then in expectation it would be worse than Second Doses First (95% efficacy) but if there were lots uncertainty around the 45% expected efficacy it might still be better to switch to First Doses First. If there was a 75% chance that the efficacy of the first dose was 30%, for example, and a 25% chance that it was 90% (.75*.3+.25*.90=45%) then under reversibility one would still want to switch to First Doses First to learn whether the true efficacy was 30% or 90%.*

Put differently shifting away from the default strategy to an alternative such as FDF or fractional dosing might be considered to be “risky”. But in this context, learning requires risk. When learning is desirable, it is also desirable to take on risk. Risk aversion can prevent learning and thus can be dangerous.

If FDF is worse in expectation than SDF then it would be optimal to switch to the most minimal form of FDF necessary to learn about the true efficacy rate. In other words, to run an experiment. If FDF is superior in expectation to SDF then it might also be better to run an experiment before switching but not necessarily. If FDF is superior in expectation to SDF then the cost of running the experiment is keeping the policy with lower expected value while the experiment is running. If these costs are high then switching immediately is better.

It would take at least 16 weeks, for example, to run an experiment on extending dosing from 3 weeks to 12 weeks (including, optimistically, just 1 week to setup the experiment). As of early January 2021, confirmed cases in the United States are increasing at the rate of 200,000 per day or 1,400,000 per week. Thus there could be 22,400,000 new confirmed cases in the time it takes to run the experiment. At a case fatality rate of 1.7% that means 380,800 new deaths. If First Doses First reduces the infection rate in expectation by 10% that would imply that running the experiment has an expected cost of 38,080 lives.

At these rates, more lives could be saved in expectation by switching to the policy with higher expected value and simultaneously running experiments. Randomized trials that explicitly test the impact of dosing timing, fractional dosing and different timings of additional doses on severe, symptomatic and asymptomatic infections, and also on transmission should be incorporated as part of roll-out plans (Kominers and Tabarrok 2020, Bach 2021). However, roll-out of modified plans should not wait until these trial results are known; instead, plans should be adjusted as new information emerges. Most notably the British moved to First Doses First and they approved the AstaZeneca vaccine on December 30, 2020 and the consequences of both of these decisions should be monitored very closely to help improve decisions in other countries.

*This assumes that one could learn the true efficacy rate quickly enough relative to the ongoing pandemic to benefit from the new information. One might respond that in principle SDF also contains an option to switch to FDF but this option is valueless since Second Doses First provides no opportunity to learn. Only under First Doses First do we learn valuable new information.

Be Prepared! Sars-COV-3

The federal government was unprepared for the pandemic, despite multiple, loud and clear warnings. State and local governments were unprepared for vaccines, despite multiple, loud and clear warnings. The Capitol Police were unprepared for rioters, despite multiple, loud and clear warnings.

The record isn’t good but as a Queen’s Scout I persist. We now have multiple, loud and clear warnings that new variants of the SARS-COV II virus are more transmissible and thus much more dangerous. But we can do something. As wrote in The New Strain and the Need for Speed

One of the big virtues of mRNA vaccines is that much like switching a bottling plant from Sprite to 7-Up we could tweak the formula and produce a new vaccine using exactly the same manufacturing plants. Moreover, Marks and Hahn at the FDA have said that the FDA would not require new clinical trials for safety and efficacy just smaller, shorter trials for immune response (similarly we don’t do new large-scale clinical trials for every iteration of the flu vaccine.) Thus, if we needed it, we could modify mRNA vaccines (not other types) for a new variant in say 8-12 weeks.

Thus, let’s start doing much more sequencing to discover new strains–and also think about potential new strains–and start phase I and phase II trials of new vaccines. Florian Krammer suggested an even more ambitious plan to do the same thing for all potential pandemic viruses:

From each of the identified virus families, which should certainly include the Paramyxoviridae, Orthomyxoviridae, and Coronaviridae families, a handful of representative strains with the highest pandemic potential should be selected for vaccine production. Up to 50–100 different viruses could be selected and this would broadly cover all phylogenies that may give rise to pandemic strains….It should be possible to choose candidates that are close to viruses that might emerge in the human population. The idea is that once viruses are selected, vaccines can be produced in different platforms and tested in phase 1 and phase 2 trials with some of the produced vaccine being stockpiled. This would likely cost 20–30 million US dollars per vaccine candidate resulting in a cost of 1–3 billion US dollars.

What I am suggesting is less ambitious–just do this for Sars-COV-3, 4, 5 and 6. But do it now!

Hat tip: Daniel Bier.

Broken Record Addendum: We should make better use of our limited vaccine supply by moving to First Doses First and/or fractional dosing and approve the AstraZeneca vaccine immediately and spend billions to increase the rate of vaccinations and to speed new vaccines (such as those from J&J and Novavax) to market.