Last week, the Food and Drug Administration and the Centers for Disease Control and Prevention authorized a fourth dose of the COVID-19 vaccine for people 50 years and older, as well as some immunocompromised people.
The decision was made at a time when COVID-19 cases and hospitalizations in the United States have been declining. At the moment, more than 99% of U.S. counties have low or medium COVID-19 community levels, according to CDC data.
So why would someone need another booster at a time where the virus is circulating at relatively low levels? Yahoo News spoke to Katelyn Jetelina, an epidemiologist at the University of Texas Health Science Center, to break down what Americans need to know about the second booster.
There are two main reasons that U.S. federal health agencies recommend another booster for some higher-risk individuals. One reason is that there’s some evidence that vaccine protection against infection and serious outcomes from COVID-19 wanes over time, particularly for those who are older and immunocompromised.
One study conducted by the CDC found that vaccine effectiveness against Omicron, a COVID variant that is more transmissible and can evade vaccine immunity, was decreasing over time. According to the study, vaccine effectiveness against emergency and urgent care visits was 87% two months after a third dose, but it decreased to 66% by the fourth month after a third dose. Vaccine effectiveness against hospitalizations was also slightly decreasing, although the study showed it largely held up five months after the third dose.
Another reason a second booster is recommended at this time is that the United States is bracing for a new COVID-19 wave driven by a more transmissible Omicron subvariant known as BA.2. The strain, which has been driving new COVID-19 surges in China, the United Kingdom and Europe, has recently become dominant in the U.S., according to CDC data. BA.2 now accounts for about 72% of new coronavirus cases nationwide, according to the agency.
There are early signs that the BA.2 infection wave has already begun. Over the past two weeks more than a dozen states, the majority in the Northeast, have seen an uptick in cases. In New York, Massachusetts and New Jersey, cases are up by more than 30 percent, according to New York Times data.
Although the ultimate impact of BA.2 in the U.S. is yet to be seen, health experts don’t foresee the variant causing a major surge as it did in Europe. However, Jetelina says deploying an additional booster now is a “proactive move” to stay one step ahead of the virus, which “is mutating pretty quickly.”
“Too many people have waning antibodies, and there’s still a benefit to protecting against that new wave that may or may not come,” she said.
Based on the FDA and CDC recommendation, a second booster of the Pfizer-BioNTech or Moderna vaccines may now be administered to certain immunocompromised individuals and people 50 and older at least 4 months after they received a first booster dose of any authorized or approved COVID-19 vaccine.
People 12 and older with certain kinds of autoimmune disorders, such as those who have undergone organ transplants, will also be eligible for a second booster dose of the Pfizer shot, the FDA said, while those 18 and older who are qualified to receive a shot can choose between Pfizer’s and Moderna’s.
The CDC is also recommending that adults who received the one-dose Johnson & Johnson primary series and received a booster at least four months ago get a second booster using one of the two mRNA COVID-19 vaccines available — Moderna or Pfizer.
Many people are asking why both the FDA and the CDC are recommending the additional dose for people ages 50 years and older when most of the research in Israel that drove the decision studied individuals who are 60 and older. On Monday, Peter Marks, who oversees the FDA’s vaccine division, explained why.
“The reason why we felt it was very reasonable to include the 50 to 65 age range is because about a third of people in the United States in that age range have medical comorbidities,” Marks said on “In the Bubble with Andy Slavitt” podcast. “The safety is excellent and the idea here is that, you know, it is sometimes easier to just say, ‘Look, we know in general with respiratory viruses people over 50 years of age tend to have more problems than people under 50 years of age. Maybe it’s a good idea just to boost everyone here in the event we have another wave,’” he added.