COVID-19 boosters extend the protection granted by COVID-19 shots. But for how long? Two new studies found that while boosters protect a significant amount, their benefits wane after a certain amount of time.
The studies were published by the Centers for Disease Control (CDC), and found that, on average, protection wanes four months after the booster shot. This evidence makes some researchers believe that boosters will be necessary until the pandemic is under control.
Researchers examined the records of more than 200,000 visits to the emergency room and urgent care and over 90,000 hospitalizations, all taking place between August 2021 and January 2022. Researchers were able to notice more protection after patients had their third dose but were also able to pinpoint the moment where protection waned.
Two months after the third dose, there was 87% protection in emergency and urgent care visits, and 91% protection against hospitalizations. By the fourth month, these numbers fell to 66% and 78% respectively.
Evidence of waning immunity was not only present in Omicron cases. Previous data, from the time when Delta was the dominant strain, also showed that patients lost their immunity with the passage of time.
The CDC concluded their findings by stating that the “underscore the importance of receiving a third dose of mRNA COVID-19 vaccine to prevent both COVID-19-associated ED/UC encounters and COVID-19 hospitalizations among adults.”