COVID booster effectiveness wanes after 3 months, study shows

Data in a new clinical trial was consistent with real-world reports showing waning protection against COVID-19 infection during the Omicron wave in people who received vaccines and a booster.

 The COVID-19 vaccine (illustrative). (photo credit: PIXABAY)
The COVID-19 vaccine (illustrative).
(photo credit: PIXABAY)

COVID-19 vaccines have successfully prevented hospitalizations and deaths, but a new study confirms that the antibody levels they provide decrease substantially within three months.

The research, conducted in a clinical trial by the National Institutes of Health, was published Tuesday in Cell Reports Medicine. It looked specifically at the Omicron variant of COVID-19, which has been notoriously tricky, evading the body's defenses from prior vaccinations in a way earlier variants had not been able to and causing the extremely aggressive fifth wave of the pandemic at the end of 2021.

To test the theory, investigators administered COVID-19 booster vaccines to adults in the United States who had previously received a primary COVID-19 vaccination series under Emergency Use Authorization. Some participants received the same vaccine as their initial series, while others received a different vaccine. Their immune responses were watched over a period of time. 

 Vials containing the corona vaccine and a syringe are displayed in front of an Israeli flag. (credit: DADO RUVIC/REUTERS) Vials containing the corona vaccine and a syringe are displayed in front of an Israeli flag. (credit: DADO RUVIC/REUTERS)

Study results 

Immune responses to Omicron in all groups waned substantially, with neutralizing antibody levels decreasing 2.4- to 5.3-fold by three months post-boost.

Researchers said that the data was consistent with real-world reports showing waning protection against coronavirus infection during the Omicron wave in people who received a primary vaccine series plus a booster shot. They noted that the findings could be used to inform decisions regarding future vaccine schedule recommendations, including the need for variant vaccine boosting.

Booster shots crucial

Despite short-lived protection, coronavirus vaccine boosters are crucial in order to maintain the body's immunity to infection, a different study, also published this week, said.

The new study by the Yale School of Public Health showed that peak antibody levels achieved by getting vaccinated with an mRNA vaccine exceed those gained from natural infection, meaning that those vaccinated are more protected from reinfection than those who are not vaccinated and have healed from COVID-19. The Yale study notes that one must keep up with booster shots because of waning.