Convalescent Blood Therapy

A simple and medically feasible strategy is available now for treating COVID-19 patients, transfuse blood plasma from recovered patients. The idea is that the antibodies from the recovered patients will help the infected patients. The idea is an old one and has been used before with some success. Here is Robert Kruse from Johns Hopkins (who also makes other suggestions):

A simple but potentially very effective tool that can be used in infectious outbreaks is to use the serum of patients who have recovered from the virus to treat patients who contract the virus in the future. Patients with resolved viral infection will develop a polyclonal antibody immune response to different viral antigens of 2019-nCoV. Some of these polyclonal anti-bodies will likely neutralize the virus and prevent new rounds of infection, and the patients with resolved infection should produce 2019-nCoV antibodies in high titer.Patients with resolved cases of 2019-nCoV can simply donate plasma, and then this plasma can be transfused into infected patients. Given that plasma donation is well established, and the transfusion of plasma is also routine medical care, this proposal does not need any new science or medical approvals in order to be put into place. Indeed, the same rationale was used in the treatment of several Ebola patients with convalescent serum during the outbreak in 2014–2015, including two American healthcare workers who became infected.

As the outbreak continues, more patients who survived infection will become available to serve as donors to make antisera for 2019-nCoV, and a sizeable stock of antisera could be developed to serve as a treatment for the sickest patients.

Kruse worries that the exponential growth of the pandemic will be too fast but I think he makes a mistake. The number of recovered patients will far exceed the number of hospitalized patients so the supply of plasma will rise more quickly than the demand.

Convalescent blood therapy was used to treat people during the 1918 flu pandemic and appeared to be useful (see here for references to papers from that time.) A recent meta-analysis of patients treated with blood therapy during the 1918 flu found good results (noting, of course, that data from a hundred years ago wasn’t ideal) :

Patients with Spanish influenza pneumonia who received influenza-convalescent human blood products may have experienced a clinically important reduction in the risk for death. Convalescent human H5N1 plasma could be an effective, timely, and widely available treatment that should be studied in clinical trials.

Blood therapy has also been used periodically since that time to treat Ebola patients, MERS patients, Junin patients and others but under non-ideal conditions where lots of things were being tried at the same time and controls were not ideal. Results have been mostly positive or non-negative, e.g. this study on 84 Ebola patients found few benefits but also small costs. Blood therapy has also been used for animals.

To implement we need a database of recovered patients. The recovered patients then needed to be tested to find those with the most antibodies. It is probably best to use recovered patients from the same location to maximize overlap although the Chinese brought plasma from China to Italy. Most of the dangers from blood transfusion such as passing on another disease are well understood and should be manageable with testing and knowledge of donors. In rare cases such as Dengue it can bad to stimulate the immune system (see discussion here).

Plasma therapy is not difficult and there are firms with expertise in the field including Takeda and Regenernon the latter of whom developed a blood based treatment for Ebola. Thus, CBP seems worthy of consideration.

Hat tip: Monique van Hoek.


Comments for this post are closed