New COVID boosters that target the fast-spreading Omicron strains of the virus are rolling out this week, with the CDC recommending these so-called bivalent mRNA shots for Americans 12 and older.
Here are answers to frequently asked questions about the shots produced by Moderna and Pfizer/BioNTech, based on information provided by the CDC and Keri Althoff, PhD, and virologist Andrew Pekosz, PhD, Johns Hopkins Bloomberg School of Public Health epidemiologists.
Q: Who is eligible for the new bivalent boosters?
A: The CDC greenlighted the upgraded Pfizer/BioNTech shots for Americans 12 and older and the Moderna booster for those 18 and over, if they have received a primary vaccine series or a booster at least 2 months before.
The boosters have been redesigned to protect against the predominant BA.4 and BA.5 strains of the virus. The Biden administration is making 160 million of the booster shots available free of charge through pharmacies, doctor's offices, clinics, and state health departments.
Q: What about children under 12?
A: The new boosters are not approved for children under 12. Additional testing and trials need to be conducted for safety and effectiveness. But officials recommend that children 5 and above receive the primary vaccine series and be boosted with one shot. Children 6 months to under 5 years are not yet eligible for boosters.
Pfizer said it hopes to ask the FDA for authorization in 5- to 11-year-olds in October.
Q: How do the new bivalent boosters differ from previous shots?
A: The new shots use the same mRNA technology as the prior Moderna and Pfizer/BioNTech vaccines and boosters but have been upgraded to target the newer Omicron strains. The shots use mRNA created in a lab to teach our cells to produce a specific protein that triggers an immune-system response and make antibodies that help protect us from of SARS-CoV-2, the virus that causes COVID.
The recipe for the new shots incorporates the so-called "spike protein" of both the original (ancestral) strain of the virus and more highly transmissible Omicron strains (BA.4, BA.5). Once your body produces these proteins, your immune system kicks into gear to mount a response.
It's also possible – but yet to be determined – that the new bivalent boosters will offer protection against newer but less common strains known as BA.4.6 and BA.2.75.
Q: Are there any new risks or side effects associated with these boosters?
A: Health experts don't expect to see anything beyond what has already been noted with prior mRNA vaccines, with the vast majority of recipients experiencing only mild issues such as redness from the shot, soreness, and fatigue.
Q: Do I need one of the new shots if I've already had past boosters or had COVID?
Yes. Even if you've been infected with COVID in the past year and/or received the prior series of primary vaccines and boosters, you should get a bivalent Omicron shot.
Doing so will give you broader immunity against COVID and also help limit the emergence of other variants. The more Americans with high immunity, the better; it makes it less likely other variants will emerge that can escape the immunity provided by vaccines and COVID infections.
Q: How long should I wait, from the time of my last shot, before getting a new booster?
A: The bivalent boosters are most effective when given after a period of time has passed between your last shot and the new one. A 2-to-3-month waiting period is the minimum, but some evidence suggests extending it out to 4 to 6 months might be good timing.
To determine when you should get a new booster, check out the CDC'sStay Up to Date with COVID-19 Vaccines Including Boosters website.
Q: What if I've recently had COVID?
A: There are no specific rules about a waiting period after COVID infection. But if you have been infected with the virus in the last 8 weeks, you may want to wait for 8 weeks to pass before receiving the bivalent booster to allow your immune system to get greater benefit from the shot.
Q: If I never got the original vaccines, do I need to get those shots first?
A: Yes. The bivalent vaccine has a lower dose of mRNA than the vaccines used in the primary series of vaccines, rolled out in late 2020. The bivalent vaccine is authorized for use as a booster dose and not a primary vaccine series dose.
Q: Do the Omicron-specific boosters entirely replace the other boosters?
A: Yes. The new booster shots, which target the original strain and the Omicron subvariants, are now the only available boosters for people ages 12 and older. The FDA no longer authorizes the previous booster doses for people in the approved age groups.
Q: What if I received a non-mRNA vaccine produced by Novavax or Johnson & Johnson? Should I still get an mRNA booster?
A: You can mix and match COVID vaccines, and you are eligible to get the bivalent booster 8 weeks after completing the primary COVID vaccination series – whether that was two doses of mRNA or Novavax, or one shot of J&J.
Q: How effective are the new boosters?
A: Scientists don't have complete effectiveness data from the bivalent vaccines yet. But because the new boosters contain mRNA from the Omicron and the original strains, they are believed to offer greater protection against COVID overall.
Cellular-level data supports this, with studies showing the bivalent vaccines increase neutralizing antibodies to BA.4/BA.5 strains. Scientists regard these kinds of studies as surrogate stand-ins for clinical trials. But officials will be studying the effectiveness of the new boosters, examining to what degree they reduce hospitalizations and deaths.
Q: How long will the boosters' protection last?
A: Research shows that vaccine effectiveness eventually wanes, which is why we have the boosters. Scientists will be monitoring to see how long the protection lasts from the bivalent boosters through studies of antibody levels as well as assessments of severe COVID illnesses over time, throughout the fall and winter.
Q: Is it OK to get a flu shot and a COVID booster at the same time?
A: Yes. In fact, it's important to get a flu shot this year because some experts believe we could see overlapping COVID-influenza surges this fall – a phenomenon some have fancifully called a "twindemic." Getting a flu shot and COVID booster -- simultaneously, if possible – is particularly important if you're in a high-risk group.
People who are susceptible to severe complications from COVID -- such as older people, people with weakened immune systems, and those will chronic health conditions -- are also especially vulnerable to severe influenza complications.
Q: Will a new booster mean I can stop wearing a mask, social distancing, avoiding crowded indoor spaces, and taking other precautions to avoid COVID?
A: No. It's still a good idea to mask up, keep your distance from others, avoid indoor spaces with people whose vaccine status is unknown, and take other precautions against COVID.
Although the new boosters are front of mind, it's a good idea to also use other tools in the toolbox, as well, particularly if you have contact with someone who is older, immune-suppressed, has a chronic condition that puts them at higher risk from COVID.
Keep in mind: The community risk of infection nationwide is still high today, with about 67,400 new cases and nearly 320 deaths reported each day in the U.S., according to the latest CDC reports.
News briefing, Johns Hopkins Bloomberg School of Public Health, Sept. 8, 2022.
Keri Althoff, PhD, epidemiologist, Johns Hopkins Bloomberg School of Public Health.
Andrew Pekosz, PhD, epidemiologist, Johns Hopkins Bloomberg School of Public Health.
Reuters: "U.S. CDC backs use of redesigned Omicron COVID boosters."
CDC: "Stay Up to Date with COVID-19 Vaccines Including Boosters," "Understanding mRNA COVID-19 Vaccines," "COVID Data Tracker."
The New York Times: "What to know About the New Booster Shots."
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Cite this: FAQ: New COVID Omicron Boosters - Medscape - Sep 12, 2022.