By Mary Kekatos, U.S. Health Editor for DailyMail.com
What are COVID-19 vaccine boosters?
A booster shot is given at least two months after people have been fully vaccinated against COVID-19.
It is meant to prolong immunity and give a ‘boost’ to the immune system to create higher levels of antibodies against the virus.
Is vaccine protection waning?
Several studies have recently suggested that vaccine protection does decrease over time.
A recent study from the Public Health Institute in Oakland, California, found that the overall effectiveness of the three Covid vaccines available in the U.S. fell from 87% in March to 48% by September.
Johnson & Johnson’s vaccine saw its protection wane the most, dropping from 86% in March to below 50% by September, and down to only 13% in October.
The Pfizer-BioNTech jab saw its effectiveness drop from 87% in March to 43% in September.
Moderna’s shot held up the best, but still fell from 89% in March to 58% in September.
However, health officials insist that vaccines are still highly effective against the most severe outcomes from COVID-19, including hospitalization and death.
Additionally, some people have weakened immune systems, either due to medical conditions or to age, that have left them unable to mount a full immune response to the first doses.
Who is currently eligible?
All U.S. adults aged 18 and older who are fully vaccinated can receive a booster shot.
The first group authorized to receive boosters was Americans with compromised immune systems, with that decision coming in August.
Next, the U.S. Food and Drug Administration (FDA) expanded that authorization to specific at-risk groups.
These included people aged 65 and older, long-term care facility residents and people aged 18 to 64 at high risk of severe COVID-19 due to underlying medical conditions.
Also authorized are those at high risk due to their jobs or other factors, such as healthcare workers, teachers and grocery store employees – and those who live in institutional settings that increase their risk of exposure, such as prisons or homeless shelters.
In November, this authorization was expanded to include all adults regardless of risk factors for severe illness.
Which COVID-19 vaccine booster can I get?
Americans can get any of the three authorized boosters.
Pfizer-BioNTech’s and Moderna’s booster shots are administered at least six months after the final shot.
J&J’s booster shot is given at least two months after the final dose.
Pfizer’s and J&J’s booster shots are exactly the same – both ingredients-wise and dosage (30 micrograms and 0.5 milliliters, respectively) – as the primary doses.
Moderna’s booster shot is 50 micrograms – half the dosage of its original vaccine.
Can I mix and match?
Yes, federal health officials say Americans can get booster shots made by a different vaccine manufacturer than that of their initial doses.
Researchers from the National Institutes of Health presented data at an FDA advisory committee meeting in October showing the effectiveness of mixing-and-matching.
The report found that when recipients of the one-shot J&J vaccine received a second dose, their antibody levels increased four-fold over two weeks.
Comparatively, when they received a Moderna booster, their antibody levels spiked 76-fold over the same time period.
A booster shot of the Pfizer vaccine also raised antibody levels 45-fold over the course of two weeks – higher than the J&J shot, but not as high as the Moderna shot.
What’s more, the Moderna booster was also found to raise antibody levels higher Pfizer recipients.
Americans who received two doses of the Pfizer saw their antibody levels increase 21-fold after a third Pfizer shot.
But those given the Moderna booster had antibody levels raised 32-fold over the span of 14 days.