If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.




A fourth jab boosts immunity

Researchers quantify the immune response to second booster shots of mRNA-based COVID-19 vaccines

by Laura Howes
May 14, 2022 | A version of this story appeared in Volume 100, Issue 17


A nurse sucks a dose of COVID-19 vaccine into a needle in front of a woman wearing a mask, who has pulled down her cardigan to reveal her upper arm.
Credit: Shutterstock
Fourth doses on messenger RNA–based COVID vaccines boost immunity beyond previous levels.

The UK-based COV-Boost trial has found that fourth doses of messenger RNA (mRNA) vaccines give people even higher levels of protective antibodies against SARS-CoV-2 than they gained from their third dose (Lancet Infect. Dis. 2022, DOI: 10.1016/S1473-3099(22)00271-7). The trial research team, led by Saul Faust of the University of Southampton, measured antibody levels and immune cell activation in 133 participants after they received either a full dose of BioNTech and Pfizer’s Comirnaty vaccine or a half dose of Moderna’s Spikevax as a fourth vaccination. The trial participants had all received a Comirnaty booster at least 7 months before. The researchers recorded any side effects participants experienced after the new booster and measured antibody and T-cell levels at the time of the shot and 14 days later. Participants had even more antibodies targeting the spike protein than they had after the third dose—meaning that fourth doses don’t just top up immunity but increase it. The boosting benefit was less pronounced for those in the study who had retained high antibody levels from their third dose. According to the COV-Boost team, this finding hints that there may be a ceiling to vaccine-acquired immunity with current vaccines. More studies will be needed to determine that. More importantly, Faust said at a press conference, fourth doses “produce a substantial boost to both the antibody and cellular immunity.” The COV-Boost study will monitor the trial cohort to see how the immunity changes over time.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.