COVID-19 booster effectiveness wanes after 4 months, CDC says

According to a new study released on Friday, the third dose of the coronavirus vaccines lose significant efficacy after around four months, meaning they are less likely to prevent severe illness.

Booster effectiveness against hospitalizations during the wave of the omicron variant dropped from 91 percent in the first two months to 78 percent at the four month mark, as shown by data from the Centers for Disease Control and Prevention.

Additionally, the booster’s effectiveness in preventing emergency department or urgent care visits within that same time frame dropped from 87 percent in two months to 66 percent in the fourth month following the third dose. Effectiveness further dropped to 37 percent after five months.

The CDC recommended in their summary of the study that all eligible people “remain up to date with recommended COVID-19 vaccinations to best protect against COVID-19-associated hospitalizations and [emergency and urgent care] visits.” 

The study was conducted with cases spanning 10 states from August 26, 2021 to January 22, 2022. Data gathered suggests that vaccine protection is stronger generally against hospitalizations than it is for emergency visits.

The vaccines also seemed to be more effective when the delta strain was the primary variant causing infection than when omicron rose and began spreading. 

Dr. Anthony Fauci, the White House’s chief medical adviser and director of the National Institute of Allergy and Infectious Diseases, recently said in a statement to the Financial Times that he foresees an era coming soon where vaccines and prior infections mean COVID-19 restrictions will be lessened.

He added that regular boosters might not be needed for everyone. “It will depend on who you are,” Fauci noted. “But if you are a normal, healthy 30-year-old person with no underlying conditions, you might need a booster only every four or five years.”