Vaccine and Antibodies

Vaccine Immunity:

In December of 2020, the FDA issued emergency use authorization for two vaccines: Pfizer-BioNTech (BNT162b2) COVID-19 Vaccine and the Moderna (mRNA-1273) COVID-19 Vaccine. When approved, the Moderna vaccine had a 94.1% efficacy rate, while the Pfizer vaccine had a 95% efficacy rate in protecting against COVID-19. These efficacy rates are after completing the full schedule of two doses of the vaccine. On February 27, 2021, the FDA issued the third emergency use authorization for the Janssen COVID-19 Vaccine. This vaccine is a one-dose vaccine, and has an efficacy rate of 85% 28 days after receiving the vaccine. On April 13, 2021, the FDA and CDC have recommended a pause on the Janssen vaccine. 

Antibody response to the different vaccines is still being reviewed. The main concern is the durability of antibody response after the vaccination. While we don’t know how effective the vaccine will be against the new strains, researchers are hopeful that the vaccines will prevent mild and moderate cases. A report on the durability of responses after the mRNA-1273 (Moderna) vaccine showed that 43 days after the first vaccination, CD4 type 1 helper T cells had responded, which shows the potential of long-term humoral immunity. While antibody response slightly declined, all participants at 3 months had elevated levels of binding and neutralizing antibodies. A study looking at the BNT162b2 (Pfizer-BioNTech) vaccine showed strong antibody responses 7 days after the second dose of the vaccine (day 29). All participants within the study vaccinated with the BNT162b2 vaccine had S-specific CD4+ T cell responses. CD8+ T cell responses were reported in 92% of participants that were vaccinated.

The most up to date information about COVID-19 vaccines can be found on the CDC website.