A year ago, just two doses of a Covid-19 vaccine — or even one, in the case of Johnson & Johnson’s formulation — were thought to offer sufficient protection against the coronavirus.
Now, faced with the extraordinarily contagious Omicron variant, Israel has begun offering fourth doses to some high-risk groups. On Wednesday, the Centers for Disease Control and Prevention expanded eligibility for boosters to adolescents and backed away from describing anyone as “fully vaccinated” because two shots no longer seem adequate.
Instead, one’s vaccination status will now be “up to date” — or not. It’s no surprise that many Americans are wondering: Where does this end? Are we to roll up our sleeves for booster shots every few months?
Humbled repeatedly by a virus that has defied expectations, scientists are reluctant to predict the future. But in interviews this week, nearly a dozen said that whatever happens, trying to boost the entire population every few months is not realistic. Nor does it make much scientific sense.
“It’s not unheard-of to give vaccines periodically, but I think there are better ways than doing boosters every six months,” said Akiko Iwasaki, an immunologist at Yale University. Other strategies, she said, could “get us out of this forever-boosting kind of a situation.”
For starters, persuading people to line up for shots every few months is probably a losing proposition. Just as important, there are no data to support the effectiveness of a fourth dose of the current vaccines.
Pfizer-BioNTech, Moderna and Johnson & Johnson have all said that they are testing vaccines targeting Omicron that may become available in a few months.
“It doesn’t make sense to keep boosting against a strain that’s already gone,” said Ali Ellebedy, an immunologist at Washington University in St. Louis. “If you are going to add one more dose after three, I would definitely wait for an Omicron-based one.”