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BOOSTING MORALE How to decide whether to get a booster dose — and which one, if you do BY TINA HESMAN SAEY, SCIENCE NEWS
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t’s been a little over six months since I got my second dose of the COVID-19 vaccine from Pfizer and its German partner BioNTech, and a phone call from my state health department over the weekend reminded me that I am eligible for a booster. But do I really need to get a third COVID-19 shot? If so, which of the three authorized or approved vaccines available in the United States should I get? To make my decision, I looked at the evidence and talked to some experts. What I found out could be useful to anyone deciding on a booster. Let’s start with Johnson & Johnson. Everyone who got that shot as their initial vaccine is recommended to get a booster two months after the first jab, U.S. health officials and experts say. That’s because the antibody response from that one-dose vaccine isn’t as high as for the two-dose mRNA vaccines from Pfizer and Moderna, and it is waning. “It doesn’t go away entirely,” says Sachin Nagrani, medical director of Heal, a company that provides primary health care in people’s homes via telehealth visits and house calls. But a few months after the J&J shot, “it seems like your immune response is less protective.” There are few studies on J&J boosters, but the
AstraZeneca vaccine, which is built on similar technology but not available in the United States, could provide some clues. Both vaccines use adenoviruses to deliver DNA instructions for building the coronavirus’ spike protein to cells. Studies show combining AstraZeneca’s COVID-19 vaccine with a boost from the Pfizer shot (or sometimes Moderna) was more effective than getting another dose of AstraZeneca. For instance, in Sweden, a double dose of AstraZeneca was about 50 percent effective at preventing symptomatic illness. But AstraZeneca followed by Pfizer was 67 percent effective and AstraZeneca boosted with Moderna was 79 effective, researchers reported Oct. 18 in the Lancet Regional Health — Europe. A preliminary study that mixed and matched vaccines in the United States found that people who got J&J as their first dose developed much higher levels of antibodies if their second dose was an mRNA vaccine than if it was another jab of J&J. Those data suggest that people who got vaxxed with J&J should consider getting an mRNA booster. On Nov. 19, the U.S. Food and Drug Administration
authorized mRNA boosters for everyone 18 and older. Some states were already allowing all adults to get boosted prior to the FDA decision. An advisory committee for the U.S. Centers for Disease Control and Prevention gave its unanimous blessing and CDC director Rochelle Walensky signed off on the expanded recommendations later that day. But some experts question whether the additional doses are really necessary for most people. I considered risk factors before deciding whether I needed the shot. When I was contemplating my choice, boosters were recommended for people 65 and older, who are at risk of severe illness and death from COVID-19. I’m younger than that and fall into the CDC panel’s recommendation that people 50 and older should get a booster. Those in the 18- to 49-year-old age group may get a third dose but don’t necessarily need an additional shot the way I and other middle-aged and older people do. People who have a high chance of getting exposed to COVID-19 through their jobs or living situations have also been advised to get a booster. But right now I work from home, where just my husband and I live. People with certain underlying health conditions are at greater risk of severe disease. I do have a couple of health conditions that make me more vulnerable. But how much more benefit would I get from a booster shot than from the two doses I already received? Much of what we know about mRNA booster shots comes from data collected in Israel, where everyone 12 and older has been eligible for a third dose of the Pfizer vaccine since the end of August. People who were fully vaccinated with two doses of the vaccine and had no underlying health
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DEC. 8-14, 2021 ● ORLANDO WEEKLY
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