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5 things to know about omicron variant, booster shots

Should you still get your COVID-19 booster shot now that omicron is here? Here’s what you need to know.
Family nurse practitioner Elyse Roelans draws a dose of the Moderna COVID-19 vaccine at a CVS Minute Clinic in Davie on Thursday, Nov. 18, 2021.
Family nurse practitioner Elyse Roelans draws a dose of the Moderna COVID-19 vaccine at a CVS Minute Clinic in Davie on Thursday, Nov. 18, 2021. [ South Florida Sun Sentinel ]
Published Dec. 9, 2021|Updated Dec. 14, 2021

The quick-spreading omicron variant of the coronavirus has made its inevitable appearance in Florida.

As residents of the Sunshine State and across the globe wait for more information on how contagious, how deadly and how easily the variant can evade immunity protections, there’s been a renewed focus among many public health experts to get booster shots — or, in some cases, initial vaccine doses — into people’s arms.

The Centers for Disease Control and Prevention updated its guidance last week and now says that everyone ages 16 and older can get a booster shot. It says the emergence of the omicron variant “further emphasizes” the importance of vaccinations and boosters and other protection efforts.

Related: U.S. swiftly approves Pfizer COVID boosters for ages 16, 17

All three vaccine manufacturers approved in the U.S. — Pfizer-BioNTech, Moderna and Johnson & Johnson — have boosters available. Pfizer is the only vaccine approved for minors, and it is not yet known whether ages 5 to 15 will also need an extra dose.

More booster shots are being doled out in Florida as news of the emergence of the omicron variant spreads. Last week, a record 333,086 booster doses were administered in the state.

But confusion over boosters still abounds, some public health experts say, in part because of shifting federal guidelines.

“The messaging from the CDC has been kind of fragmented,” largely because data is still being collected on waning vaccine immunity and on boosters, said University of South Florida virologist Dr. Michael Teng. He said the most recent guidelines make it more straightforward.

Related: First omicron COVID cases detected in Florida, one at a Tampa VA hospital

Meanwhile, much is still unknown about the omicron variant, which some experts suggest could overtake delta within weeks.

Pfizer and BioNTech said that preliminary tests show that the companies’ two-dose vaccine may not be sufficient against the omicron variant, but that a third dose does appear to offer stronger protection.

Here are five things you need to know right now about the omicron variant and booster shots:

• • •

1. You don’t have to be older or have an underlying condition to get a booster.

Updated CDC guidance says that anyone 18 or older who got their second dose of the Pfizer or Moderna vaccines at least six months ago should get a booster shot, as should anyone 18 or older who got the single-dose Johnson & Johnson coronavirus vaccine at least two months ago. It says people aged 16 and 17 who got their second dose of the Pfizer vaccines at least six months ago can also get boosters.

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Note that side effects after the boosters appear to be similar to those experienced after the second doses of the Pfizer or Moderna vaccines, such as pain at the injection site, fatigue, headache, chills, muscle pain, fever and nausea.

In general, the CDC says side effects are a normal sign that a body is building up its protection against the virus.

Because boosters act as a reminder to a vaccinated person’s immune system, they take a shorter time to kick in, said Sally Alrabaa, an infectious disease specialist at the University of South Florida. She said one Pfizer study suggested the booster is fully effective in as early as seven days, although she said a good rule of thumb is still two weeks.

Related: How bad are COVID booster side effects? And answers to other vaccine booster questions.
• • •

2. A booster likely offers more protection from the omicron variant.

Researchers are still in the early phases of understanding the omicron variant, which Teng said is “significantly different” from some other coronavirus variants due to the large number of genetic mutations.

Early information suggests that some monoclonal antibody treatments may be less effective against this variant, and early studies suggest two-dose vaccines may not be sufficient but that immunity does appear to be aided by a third booster shot.

There are still a lot of places on the virus’s spike proteins — which current vaccines target — that aren’t affected by omicron’s mutations and are recognized by antibodies, Teng said. In other words: The variant can’t completely evade the antibodies generated by the vaccines.

And Teng said T-cells, which are another part of the body’s immune system, don’t appear to be as affected by omicron mutations.

Related: Florida adds 10,892 COVID cases, 153 deaths in past week
• • •

3. Experts say don’t wait for an omicron-specific booster shot

Pharmaceutical companies are working on boosters designed for omicron that could potentially be used against the new variant, but it’s too soon to know whether they’ll be needed. And it could take months to get such a booster ready.

Stephen Kissler, a research fellow in the Department of Immunology and Infectious Diseases at the Harvard T.H. Chan School of Public Health, recommends that people eligible for boosters not wait.

“By the time we formulate an omicron-specific vaccine and get it approved and get the supply ramped up enough to administer to everyone who wants it, omicron will already have done, basically, what it’s going to do,” said Kissler, adding that he expects an omicron surge in the “coming weeks to low numbers of months.”

Teng noted that the delta variant is still out there and is driving a surge in parts of the country.

“We’re still 99 percent delta,” Teng said. “We have to deal with the monster we’re staring at now.”

Related: Pfizer says COVID booster offers protection against omicron
• • •

4. It’s OK to mix-and-match coronavirus vaccines.

The Food & Drug Administration and CDC recommendations both allow people to pick one of the three approved vaccines — Pfizer-BioNTech, Moderna or Johnson & Johnson — for their booster shot even if it’s a different vaccine from their original doses.

Teng said that “if you really want to split hairs,” the Moderna booster may be slightly better than the others. He said people who originally got a Johnson & Johnson vaccine, which does not use mRNA technology, should consider getting Pfizer or Moderna’s mRNA vaccines two months after their shot. But he said the Johnson & Johnson vaccine also works pretty well.

The bottom line, he said, is just to get a booster. “Whatever you get, just get it,” he said.

Related: Confused about which COVID booster to get? This guide will help.
• • •

5. You don’t need to wait to get a booster if you have a cold.

People should make sure they do not have the coronavirus before they go and get a booster shot, experts say.

But as long as you’ve tested negative, there’s nothing wrong with getting a booster shot even if you’re a little sniffly.

The CDC says there’s no evidence that being sick would reduce vaccine efficacy or increase adverse reactions. But in a pre-vaccination checklist, it suggests delaying vaccines for patients with moderate or severe illness as a precaution.

And a reminder: people who have not yet gotten their flu shot can get it at the same time as their coronavirus vaccine shot or booster.

The coronavirus vaccine does not protect against the flu, and vice versa. But contracting one virus can weaken your immune system and leave you more vulnerable to the other.

Times staff writer Ian Hodgson contributed to this report.

Related: Get a flu shot and the COVID vaccine to help Florida avoid a 'twindemic'

• • •

How to get vaccinated

The COVID-19 vaccine for ages 5 and up and booster shots for eligible recipients are being administered at doctors’ offices, clinics, pharmacies, grocery stores and public vaccination sites. Many allow appointments to be booked online. Here’s how to find a site near you:

Find a site: Visit to find vaccination sites in your ZIP code.

More help: Call the National COVID-19 Vaccination Assistance Hotline.

Phone: 800-232-0233. Help is available in English, Spanish and other languages.

TTY: 888-720-7489

Disability Information and Access Line: Call 888-677-1199 or email

• • •

Tampa Bay Times coronavirus coverage

KIDS AND VACCINES: Got questions about vaccinating your kid? Here are some answers.

BOOSTER SHOTS: Confused about which COVID booster to get? This guide will help.

BOOSTER QUESTIONS: Are there side effects? Why do I need it? Here’s the answers to your questions.

PROTECTING SENIORS: Here’s how seniors can stay safe from the virus.

COVID AND THE FLU: Get a flu shot and the COVID vaccine to avoid a ‘twindemic.’

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A TRIBUTE TO FLORIDIANS TAKEN BY THE CORONAVIRUS: They were parents and retirees, police officers and doctors, imperfect but loved deeply.

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