The FDA has approved convalescent plasma for “emergency use authorization” (EUA) in treating Covid-19. This is an important tool in the medical treatment of this coronavirus and brings hope when it is seriously needed.
Naturally, those on the left and the mainstream media are accusing the FDA of playing politics with this decision. I guess this is expected since they play politics with every decision. But the FDA is merely approving what has been widely used by physicians for treating Covid-19 already; and has been in use for various illnesses since the late 19thcentury!
Ever since President Trump promoted hydroxychloroquine as a therapeutic treatment for Covid-19, the media and liberals have been out to prove him wrong and the same is happening with convalescent plasma. You would think that everyone would welcome an important breakthrough in the treatment of this dread disease, but many seem to be rooting for prolongation of the pandemic. It seems to fit their political agenda – at least until this November.
The Wall Street Journal editorial board says convalescent plasma has been used in the past to treat a wide range of illnesses including smallpox, the Spanish flu and Ebola as well as more recent respiratory viruses like H1N1, SARS, and MERS. The plasma is expected to help sick patients mount a stronger immune response by infusing them with plasma containing antibodies from recovered patients.
The immune system varies in every individual which explains why many exposed to the virus do not get sick while others do. The immune response also varies with convalescent plasma treatments; in some it produces significant improvement while others not much. This variation in response makes it difficult to evaluate effectiveness in randomized trials with control groups.
The evidence for convalescent plasma relies on more than a dozen observational studies and clinical trials that don’t meet the randomized placebo standard. One trial from Houston Methodist hospitals found that mortality among patients treated with convalescent plasma was more than 50% lower than for similar patients matched for age and underlying conditions. But the study population size wasn’t large enough to be statistically significant. Mortality was 83% loweramong a subset of patients transfused with plasma containing high levels of antibodies within 72 hours of hospital admission.
Perhaps the most persuasive evidence comes from a Mayo Clinic study, which has enrolled 90,000 hospitalized subjects since April. Although the study doesn’t include a placebo group for comparison, mortality was 21% lower among non-intubated patients treated with plasma containing high levels of antibodies versus lower levels.
Among a smaller subset of non-intubated patients below age 80 who were transfused within 72 hours of diagnosis, seven-day mortality was 44% lower among the high-antibody group. Yet the study when considering all patients did not find a difference in seven-day survival between patients transfused with higher or lower antibody plasma.
The FDA concludes, “This finding of a dose-response between antibody level and reduction in mortality provides evidence that the antibody is the active agent in convalescent plasma for treatment of Covid-19. Current evidence suggests that benefit is most likely in patients treated early in the course of the disease (e. g. prior to intubation).”
Convalescent plasma now joins remdesivir and dexamethasone as important advances in the treatment of Covid-19 until an effective vaccine is produced. The FDA was right to approve it for EUA at this time.