Moderna, J&J, Pfizer: 5 Things to Know About COVID Vaccine Booster Shots

With additional booster shots nearing authorization, questions surrounding the extra doses are rising.

The Food and Drug Administration's panel of experts is expected to evaluate boosters for both Moderna and Johnson & Johnson this week to determine if they will recommend them for emergency use. Pfizer's booster shot has already been approved for such use in certain populations.

Now, with another pivotal debate on the horizon, we took a look at some of the many questions residents have surrounding booster shots:

1. Who can currently get a booster shot?

Last month, the FDA authorized booster shots of Pfizer’s vaccine for older Americans and other groups with heightened vulnerability to COVID-19. So far, that's the only booster shot that has been approved for use.

"I would expect we'd see a series of rolling recommendations following a parallel timeframe in which the original vaccines got approved," said Dr. Daniel Kuritzkes, chief of Brigham and Women’s Hospital's infectious diseases division. "That's more of a regulatory issue. They can only act on the data they have before them."

Here's the latest list of who qualifies, according to the CDC:

• People 65 years and older and residents in long-term care settings should receive a booster shot of Pfizer-BioNTech’s COVID-19 vaccine at least 6 months after their Pfizer-BioNTech primary series,
• People aged 50–64 years with underlying medical conditions should receive a booster shot of Pfizer-BioNTech’s COVID-19 vaccine atleast 6 months after their Pfizer-BioNTech primary series,
• People aged 18–49 years with underlying medical conditions may receive a booster shot of Pfizer-BioNTech’s COVID-19 vaccine at least 6 months after their Pfizer-BioNTech primary series, based on their individual benefits and risks, and
• People aged 18-64 years who are at increased risk for COVID-19 exposure and transmission because of occupational or institutional setting may receive a booster shot of Pfizer-BioNTech’s COVID-19 vaccine at least 6 months after their Pfizer-BioNTech primary series, based on their individual benefits and risks.

What counts as a qualifying underlying health condition? Here's a list from the CDC:

• Cancer
• Chronic kidney disease
• Chronic lung diseases, including COPD, asthma (moderate-to-severe), interstitial lung disease, cystic fibrosis, and pulmonary hypertension
• Dementia or other neurological conditions
• Diabetes (type 1 or type 2)
• Down syndrome
• Heart conditions (such as heart failure, coronary artery disease, cardiomyopathies or hypertension)
• HIV infection
• Immunocompromised state (weakened immune system)
• Liver disease
• Overweight and obesity
• Pregnancy
• Sickle cell disease or thalassemia
• Smoking, current or former
• Solid organ or blood stem cell transplant
• Stroke or cerebrovascular disease, which affects blood flow to the brain
• Substance use disorders

The CDC notes that "people should talk to their healthcare provider about their medical condition, and whether getting an additional dose is appropriate for them."

The Massachusetts Department of Public Health has also put together a guide to who is eligible for a booster shot and how to access them.

2. What about those who got Moderna or J&J?

Both Moderna and Johnson & Johnson have submitted requests for emergency use authorization of their booster shots of the COVID vaccines.

"If you've had Moderna or the Jansen/Johnson & Johnson, all this discussion doesn't apply yet," Boston Medical Center's Dr. Davidson Hamer said. "So it's going to be a little bit confusing on how to move forward, at least for the time being. I think that will change."

The FDA is convening its outside panel of advisers this week to review booster data from both J&J and Moderna. It’s the first step in a review process that also includes sign-off from the leadership of both the FDA and the Centers for Disease Control and Prevention. If both agencies give the go-ahead, Americans could begin getting J&J and Moderna boosters later this month.

3. Should you get your booster 6 months after the first shot or second?

According to the guidance, those who are eligible for boosters should get their shot at least six months after receiving their second shot of the Pfizer vaccine.

Similar timing recommendations are expected soon for Moderna and J&J as well.

So what if you accidentally got it early?

Don't worry, medical experts say it shouldn't be a major issue.

4. Is the dosage amount for the Pfizer booster the exact same as the first and second dosage?

Yes.

But things get a little more complicated when you look at Moderna's booster shot.

It's possible the Moderna booster will be a slightly lower dose.

Bloomberg, citing people familiar with the matter, reported last month that the FDA was leaning toward authorizing half-dose booster shots for those who received Moderna's two-shot mRNA vaccine.

Will I get side effects from the booster?

Among people who stand to benefit from a booster, there are few risks, the CDC concluded. Serious side effects from the first two Pfizer doses are exceedingly rare, including heart inflammation that sometimes occurs in younger men. Data from Israel, which has given nearly 3 million people — mostly 60 and older — a third Pfizer dose, has uncovered no red flags.

The CDC has noted that side effects with the third shot "were similar to that of the two-dose series." The most common symptoms include fatigue and pain at the injection site, but "most symptoms were mild to moderate."

As with previous doses of the vaccine, the CDC notes that, "serious side effects are rare, but may occur."

Hamer said booster shots are safe, effective, and are unlikely to result in side effects like the initial doses.

"We've now vaccinated hundreds of millions with messenger RNA vaccines. We have a lot of safety data collected," Hamer said. "Giving a booster for most vaccines is unlikely to result in new side effects being identified... I don't anticipate any safety issues coming out as we start giving boosters."

"I completely agree," added Kuritzkes. "People need to understand there is going to be discussion. There are differences of opinion in certain aspects of how the data gets interpreted. But it shouldn't be taken in any way that there is any doubt about the efficacy and safety of these vaccines. It's all about when do we know people absolutely need to be boosted and how can we best use the vaccines we have to maximize protection for everybody, and what are the best strategies. That's where there is debate. It's not about efficacy. Simply because a booster is needed now or in the future in no way undermines the vaccine as an extraordinary tool in preventing COVID-19."