Incorrect: Scientific evidence indicates that COVID-19 vaccines don’t wipe out antibodies developed after infection. Instead, COVID-19 vaccination boosts immunity in previously infected individuals.
FULL CLAIM: “The Red Cross says anyone who has received a COVID-19 vaccine cannot donate convalescent plasma”; “the vaccine wipes out these antibodies [against SARS-CoV-2]”
This video, originally posted to TikTok and shared on social media platforms, claimed that people who received a COVID-19 vaccine can’t donate convalescent plasma because the vaccine “wipes out” natural antibodies. The video rehashed social media posts from early 2021 claiming that the COVID-19 vaccine was “untested” and convalescent plasma from vaccinated people is “tainted”. Earlier fact-checks from Reuters and PolitiFact found these claims to be false.
Convalescent plasma has been used for over a century to treat infectious diseases when no other treatment options are available. For example, it has been used to treat measles, Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome (SARS), and Ebola.
Blood can be broadly divided into two components: one component comprising cells, while the other is the liquid component, known as plasma. With convalescent plasma therapy, plasma from people who recovered from an infectious disease and developed antibodies against the disease-causing microorganism is infused into patients. The aim of this therapy is to recruit the antibody-rich plasma to assist the patient’s immune system in fighting the infection. This type of immunity is called “passive immunity”, as opposed to “active immunity” developed when the person produces his or her own antibodies, for example through vaccination.
In August 2020, the U.S. Food and Drug Administration (FDA) authorized the emergency use of convalescent plasma to treat COVID-19, after early studies suggested that it might reduce mortality and improve recovery in some hospitalized patients when administered early[1-3].
Contrary to the claim in the video, both the American Red Cross and the A.A.B.B. (formerly the American Association of Blood Banks) clearly state on their websites that individuals who received an FDA-authorized or approved COVID-19 vaccine are eligible to donate blood, platelets, and plasma as long as they are healthy and provide the vaccine manufacturer’s name. The Red Cross website specifically states:
“The FDA allows people who have received a COVID-19 vaccine to donate dedicated COVID-19 convalescent plasma within six months of their infection of the virus, based on data that antibodies from natural infection can decline after six months[…]
There are claims circulating that incorrectly state that the Red Cross will not accept convalescent plasma donations from those who have received the COVID-19 vaccine because ‘the vaccine wipes out those antibodies making the convalescent plasma ineffective in treating other COVID-19 patients.’ This is not accurate.
Due to the decline in hospital demand and because the Red Cross and our industry partners have been able to build a sufficient supply of convalescent plasma to meet the foreseeable needs of COVID-19 patients, the Red Cross stopped collecting convalescent plasma completely on June 14.”
In November 2020, when COVID-19 vaccines were still under clinical research, the FDA issued guidance excluding individuals who received an investigational COVID-19 vaccine in a clinical trial as convalescent plasma donors. After the vaccines received Emergency Use Authorization, the FDA updated guidance making individuals who received an FDA-approved or authorized COVID-19 vaccine eligible to donate convalescent plasma as long as:
- they had COVID-19 symptoms and a positive result from a diagnostic test approved, cleared, or authorized by the FDA,
- received the vaccine after being diagnosed with COVID-19, and
- are within six months of complete resolution of COVID-19 symptoms.
Although preliminary data so far is encouraging, there is currently insufficient evidence to show that convalescent plasma is an effective COVID-19 treatment. The results so far are inconclusive, with some studies showing its benefit in reducing disease severity and mortality, while others showed no effect[4-7].
The claim that COVID-19 vaccines eliminate or reduce the natural antibodies developed after infection also has no scientific basis. Health Feedback reviewed a similar claim that measles vaccination weakened the immune system against infection, and found it to be incorrect. Likewise, no scientific evidence shows that COVID-19 vaccination weakens the immune system. On the contrary, the evidence indicates that the immune system is strengthened against disease.
Several studies found that a single dose of a COVID-19 vaccine enhanced the immune response developed after infection, as well as the protection against variants of the virus[8-10]. For this reason, people who were previously infected can still benefit from COVID-19 vaccines, which act as a booster of natural immunity.
In summary, the American Red Cross does consider people who received a COVID-19 vaccine to be eligible as convalescent plasma donors. However, the organization completely stopped collecting convalescent plasma in June 2021 due to a combination of factors, specifically a sufficient supply of convalescent plasma and a decline in demand. No evidence supports the claim that COVID-19 vaccination “wipes out” antibodies against SARS-CoV-2, rather, scientific evidence shows that COVID-19 vaccines enhance protection in previously infected individuals.
- 1 – Salazar et al. (2020) Treatment of Coronavirus Disease 2019 Patients with Convalescent Plasma Reveals a Signal of Significantly Decreased Mortality. The American Journal of Pathology.
- 2 – Shen et al. (2020) Treatment of 5 Critically Ill Patients With COVID-19 With Convalescent Plasma. JAMA.
- 3 – Joyner et al. (2020) COVID-19 Convalescent Plasma in 20,000 Hospitalized Patients. Mayo Clinic Proceedings.
- 4 – Bégin et al. (2021) Convalescent plasma for hospitalized patients with COVID-19: an open-label, randomized controlled trial. Nature Medicine.
- 5 – Joyner et al. (2021) Convalescent Plasma Antibody Levels and the Risk of Death from Covid-19. New England Journal of Medicine.
- 6 – Avendaño-Solá et al. (2021) A multicenter randomized open-label clinical trial for convalescent plasma in patients hospitalized with COVID-19 pneumonia. Journal of Clinical Investigation.
- 7 – Simonovich et al. (2021) A Randomized Trial of Convalescent Plasma in Covid-19 Severe Pneumonia. New England Journal of Medicine.
- 8 – Stamatatos et al. (2021) mRNA vaccination boosts cross-variant neutralizing antibodies elicited by SARS-CoV-2 infection. Science.
- 9 – Kramer et al. (2021) Antibody Responses in Seropositive Persons after a Single Dose of SARS-CoV-2 mRNA Vaccine. New England Journal of Medicine.
- 10 – Wang et al. (2021) Naturally enhanced neutralizing breadth against SARS-CoV-2 one year after infection. Nature Medicine.