Public health officials believe the updated boosters will provide longer-lasting protection against the virus and reduce hospitalizations this fall and winter. The new boosters target both the original strain that emerged in China more than two years ago, which scientists refer to as the “wild type,” and omicron BA.4 and BA.5, which are now the dominant variants in the U.S.
Shots that target two different strains are called bivalent vaccines.
The vaccine makers developed the original vaccines against the strain of coronavirus that first emerged in Wuhan, China, in 2019. But the virus has mutated significantly since then.
As a result, vaccines’ effectiveness at preventing infection and mild illness has declined substantially as the virus has evolved. Though the vaccines are still generally effective at preventing severe disease, the protection they provide against hospitalization has diminished over time.
The redesigned boosters are only for people who have already had their primary vaccinations using the original vaccines. Doses made by Pfizer are for anyone 12 and older, while Moderna’s updated shots are for adults — if it has been at least two months since their last primary vaccination or their latest booster.
The CDC said in a statement that it “also expects to recommend updated COVID-19 boosters for other pediatric groups” in the coming weeks.
The speed of the development of these tweaked vaccines is due to a strategy that skips common steps in the testing process.
Vaccine makers have yet to complete human trials for redesigned boosters. Most of the available data on the redesigned boosters comes from lab and animal studies, causing some to question whether the data is enough to ensure the safety and efficacy of the booster.
For the first time, U.S. health officials have based their decision about whether to authorize new boosters on studies involving mice instead of humans.
But Neil Maniar, professor of practice at Northeastern’s Bouve College of Health Sciences, says it’s a “misconception,” that the booster is being developed using only mice data, considering how much we now know about the underlying technology of the vaccines.
“It’s not that we’re looking at something totally new,” he says in a piece published on Northeastern University’s news and information site. “What we’re looking at is an evolution of something that we already have a good amount of data on,” including real-world evidence of effectiveness worldwide. The mice data, he says, is really conducive to understanding the booster’s effectiveness against BA.4 and BA.5.
Brandon Dionne, associate clinical professor at Northeastern’s Bouve College of Health Sciences, added the FDA’s decision to consider COVID boosters without human data is in line with how it evaluates modified influenza vaccines every year. With the influenza vaccine— which is developed each year based on a predictive model of which strains will be prevalent in a given year —the manufacturer only has to get FDA approval using testing on humans once.
And some public health experts say waiting for more conclusive data from clinical trials could take too long and past the fall season when cases are expected to increase.
It’s not clear just how much more benefit an updated booster will bring — beyond a temporary jump in antibodies capable of fending off an omicron infection.
Still, “people have to realize this is a different kind of booster than was previously available. It will work better at protecting against omicron,” said virologist Andrew Pekosz of the Johns Hopkins Bloomberg School of Public Health.
Even people who had an earlier omicron version still can get reinfected so “you should definitely go for the booster even if you’ve been infected in the last year,” added Pekosz. He thinks “if we can get good buy-in to use this, we might really be able to make a dent” in COVID cases.
— The Associated Press and database specialist John Perry contributed to this article.
Here’s a look at some more of the latest statistics on vaccination and boosters for the U.S. and Georgia:
In the U.S., while 67% of the population is fully vaccinated, only half of those who got vaccinated — 49% — have gotten a first booster dose.
In Georgia, 57% of the population is fully vaccinated, and only 44% of those fully vaccinated have gotten their first booster dose.
In Georgia, among those 12 and over, 64% are fully vaccinated.
In Georgia, among those who are 12 and older, 27% are fully vaccinated and have received their first booster dose.