Johnson & Johnson, Moderna and Pfizer: What We Know About Booster Shots So Far

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UPDATE: The FDA on Wednesday authorized booster doses for Americans who are 65 and older, younger adults with underlying health conditions and those in jobs that put them at high risk for COVID-19. Read the latest guidance here.


Johnson & Johnson released a new update on the potential for a booster shot of its single-dose coronavirus vaccine Tuesday, but as booster shots continue to be debated nationwide, what's next for all three COVID vaccines currently being administered in the U.S.?

Pfizer, Moderna and J&J have each conducted studies surrounding booster doses of their vaccines.

Scientists inside and outside the government have been divided in recent days over the need for boosters and who should get them.

The World Health Organization has strongly objected to rich nations giving a third round of shots when poor countries don’t have enough vaccine for their first. Still, the Biden administration has said it plans to dispense COVID-19 booster shots to most Americans.

Here's what we know so far:

Can I get a booster shot?

The FDA voted to give emergency use authorization to Pfizer's COVID vaccine shot to be used as a booster for individuals who are 65 or older. Individuals with medical conditions that could lead to more severe cases of COVID are also eligible, as are individuals who work in high-risk environments.

A separate CDC panel met Thursday, voting to recommend the Pfizer booster for individuals 65 and older, as well as specific high-risk individuals.

For now, several million Americans who are especially vulnerable because of organ transplants, certain cancers or other disorders and who received the Moderna or Pfizer COVID vaccines can get a booster shot of those vaccines.

According to the CDC, the list includes people who have:

  • Been receiving active cancer treatment for tumors or cancers of the blood
  • Received an organ transplant and are taking medicine to suppress the immune system
  • Received a stem cell transplant within the last 2 years or are taking medicine to suppress the immune system
  • Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Advanced or untreated HIV infection
  • Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response

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

When might I be able to get a booster shot?

Eligible individuals will soon be able to get the Pfizer COVID vaccine boosters, with some retail outlets already accepting appointments for the shots.

The FDA and CDC will most likely decide at some later point whether people who received the Moderna or J&J shots should get boosters.

What was behind the FDA panel's decision not to allow all individuals to qualify for boosters?

Though non-binding, the FDA panel's votes represented a heavy blow to the Biden administration’s sweeping effort, announced a month ago, to shore up nearly all Americans’ protection amid the spread of the highly contagious delta variant.

Members voted against that recommendation to give a third shot of Pfizer's vaccine to individuals age 16 and up, citing concerns about the level of evidence showing the boosters are safe for younger people. 

“We’re being asked to approve this as a three-dose vaccine for people 16 years of age and older, without any clear evidence if the third dose for a younger person when compared to an elderly person is of value,” said committee member Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia.

Members cited a lack of safety data on extra doses and also raised doubts about the value of mass boosters, rather than ones targeted to specific groups.

“I don’t think a booster dose is going to significantly contribute to controlling the pandemic,” said Dr. Cody Meissner of Tufts University. “And I think it’s important that the main message we transmit is that we’ve got to get everyone two doses.”

While research suggests immunity levels in those who have been vaccinated wane over time and boosters can reverse that, the Pfizer vaccine is still highly protective against severe illness and death, even amid the delta variant.

Dr. Amanda Cohn of the CDC said: “At this moment it is clear that the unvaccinated are driving transmission in the United States.”

In a statement, Kathrin U. Jansen, Pfizer head of vaccine research and development, said the company continues to believe that boosters will be a “critical tool in the ongoing effort to control the spread of this virus.”

What about those who got Moderna or Johnson & Johnson vaccines?

The FDA and CDC will most likely decide at some later point whether people who received the Moderna or J&J shots should get boosters.

Moderna previously released data on breakthrough cases, saying it supports the push for wide use of COVID-19 vaccine booster shots.

But as the FDA's Vaccines and Related Biological Products Advisory Committee debated administering third doses of Pfizer and BioNTech's vaccine, federal health regulators say they need more time to review Moderna's application for extra doses.

Johnson & Johnson on Tuesday released data showing that a booster dose to its one-shot coronavirus vaccine provides a strong immune response months after people receive a first dose.

J&J said in statement Tuesday that it ran two early studies in people previously given its vaccine and found that a second dose produced an increased antibody response in adults from age 18 to 55. The study's results haven't yet been peer-reviewed.

The company is in talks with regulators including the U.S. Food and Drug Administration, the European Medicines Agency and others regarding using booster doses of its vaccine.

Health officials have said they were expecting to receive more data in the fall and will "keep the public informed with a timely plan for J&J booster shots as well." 

The FDA and CDC’s approval and recommendation for immunocompromised individuals does not apply to those who got the Johnson and Johnson vaccine.

If I got the Moderna or J&J vaccine should I get a booster shot of the Pfizer vaccine?

Chicago's top doctor said the answer to that question is likely no, but further information is expected when the CDC announces its decision.

"If I had gotten the Moderna vaccine, I would not personally - I would not go and get a Pfizer booster," she said. "Right now, our biggest priority is the people who are not even vaccinated at all, in terms of dropping the risk for everybody - even people who are vaccinated, continuing to keep the focus on people getting their first and second doses of vaccine is the most important thing. But my expectation is for people over 65, you'll be able to get boosters through the pharmacies, through your doctor's office through, you know, the clinics or regular immunization clinics, all of the above. So expect a more formal update and recommendations probably at the very end of this week."

For those who received the Moderna vaccine, the CDC says "a third dose of the same mRNA vaccine should be used."

"A person should not receive more than three mRNA vaccine doses. If the mRNA vaccine product given for the first two doses is not available or is unknown, either mRNA COVID-19 vaccine product may be administered," the agency's website states.

When can eligible people get their third dose?

The FDA determined that transplant recipients and others with a similar level of compromised immunity can receive a third dose of the vaccines from Pfizer and Moderna at least 28 days after getting their second shot.

Walgreens announced last month that its pharmacies will offer additional COVID-19 vaccine doses to eligible patients with compromised immune systems.

“Walgreens is committed to administering COVID-19 vaccines to our most vulnerable populations as quickly and safely as possible,” said Kevin Ban, Walgreens Chief Medical Officer. “As one of the first companies to begin providing these vaccines, we have an experienced team of pharmacists and technicians, as well as the infrastructure to support the increased demand for these vaccines.”

Walgreens has begun offering same-day appointments available to such patients on a walk-in basis at select stores, the company said. Patients will bring their vaccination card or record to the appointments to prove eligibility.

Do immunocompromised people need to get a third shot of the same vaccine they already received?

According to the CDC, "a third dose of the same mRNA vaccine should be used."

"A person should not receive more than three mRNA vaccine doses. If the mRNA vaccine product given for the first two doses is not available or is unknown, either mRNA COVID-19 vaccine product may be administered," the agency's website states.

Are there any risks with getting a booster shot? What about side effects?

The CDC reports there is "limited information about the risks of receiving an additional dose of vaccine, and the safety, efficacy, and benefit of additional doses of COVID-19 vaccine in immunocompromised people continues to be evaluated."

The agency 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."

NBC Chicago/Associated Press
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