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What to Know About the Coronavirus Vaccines

Questions continue as millions of Americans get immunized and boosted

image of a vial labeled coronavirus vaccine

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Latest updates

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  • CDC strengthens booster recommendation for older Americans. The Centers for Disease Control and Prevention (CDC) upgraded its guidance to older Americans and those age 12 and older who are immunocompromised from saying that these individuals “may” get a second COVID-19 vaccine booster shot to saying they “should” get a fourth dose. “Over the past month we have seen steady increases in cases, with a steep and substantial increase in hospitalizations for older Americans,” says a May 19 CDC statement. “While older Americans have the highest coverage of any age group of first booster doses, most older Americans received their last dose (either their primary series or their first booster dose) many months ago, leaving many who are vulnerable without the protection they may need to prevent severe disease, hospitalization and death. Whether it is your first booster or your second, if you haven’t had a vaccine dose since the beginning of December 2021 and you are eligible, now is the time to get one.”
  • CDC recommends boosters for 5 to 11 year olds. CDC Director Rochelle Walensky recommended that children 5 to 11 years old get a third dose of the Pfizer-BioNTech mRNA COVID-19 vaccine on May 19. Her recommendation follows an 11 to 1 vote by the agency’s Advisory Committee on Immunization Practices (ACIP) that these children get the extra shot five months after they receive a second dose. The U.S. Food and Drug Administration (FDA) amended the vaccine’s emergency use authorization to add the booster shot for this age group on May 17. “While it has largely been the case that COVID-19 tends to be less severe in children than adults, the omicron wave has seen more kids getting sick with the disease and being hospitalized, and children may also experience longer-term effects, even following initially mild disease,” said FDA Commissioner Robert M. Califf, M.D. Califf said the third dose is being authorized “to provide continued protection against COVID-19.” Vaccines are not yet available for children under 5, though Moderna has submitted its clinical trial data to the FDA in hopes that its shot will soon be authorized for the youngest set. The FDA’s advisory committee is expected to review the requests in June. 
  • COVID takes 1 million U.S. lives. The number of Americans who have died from COVID-19 reached 1 million on May 16.  This grim milestone eclipses the impact of other catastrophes in our nation's history. The deaths equal more than twice the American military casualties of World War II (405,399), the Vietnam War (58,220) and the terrorist attack on 9/11/2001 (2,977) — combined. These fatalities also have taken the lives of more Americans than the 657,000 who perished in the flu of 1918, also known as the Spanish flu, and the more than the 700,000 who have died from HIV/AIDS since 1981. “The fact that more than 90 percent of the 1 million COVID deaths in the U.S. over the last two years have been among those ages 50 and older spotlights the urgent need to address how we support health as we age going forward,” said AARP CEO Jo Ann Jenkins. While 1 million deaths is an overwhelming number, the breakneck development of three coronavirus vaccines that have fully immunized nearly 220 million Americans has prevented an estimated 2.2 million more fatalities from this virus, according to a Commonwealth Fund report. Yet, while hospitalizations and deaths are far lower than they were this past winter, federal health officials and medical experts are quick to point out that this pandemic is not yet behind us. And that is particularly true among Americans who are most at risk for the coronavirus: older adults, those with compromised immune systems and people with such underlying medical conditions as diabetes and respiratory illnesses.
  • FDA restricts use of Johnson & Johnson COVID vaccine. Americans 18 and older who still have not been vaccinated against COVID-19 should only get the Johnson & Johnson shot if the Pfizer -BioNTech and Moderna vaccines are not available or medically appropriate, or if getting the J&J product is the only way they will get vaccinated, federal regulators said on May 5 in an update to the vaccine’s emergency use authorization. The reason, the U.S. Food and Drug Administration (FDA ) noted in its announcement, is due to a rare but potentially life-threatening complication called thrombosis with thrombocytopenia syndrome (TTS), which was first linked to the J&J vaccine in the spring of 2021. Health officials have since been monitoring and investigating all cases of TTS, which develops when blood clots form and an individual also has low levels of blood platelets. The majority of cases — there have been 60 as of March 2022 — have been in women; most have been younger than 50. TTS has not been linked to the Pfizer-BioNTech and Moderna vaccines, which use an mRNA technology different from J&J’s. The CDC in December recommended the mRNA vaccines over J&J's product “in most situations.”
  • FDA authorizes second booster shot. The FDA has given the green light for people 50 and older to get a second COVID-19 booster shot, and the CDC has agreed and updated its vaccine recommendations. “Emerging evidence suggests that a second booster dose of an mRNA COVID-19 vaccine improves protection against severe COVID-19 and is not associated with new safety concerns,” FDA officials said in announcing the amendment to the emergency use authorization (EUA) that already provides for an initial booster shot. Under this new authorization, individuals 50 and older can get a second booster of either the Pfizer-BioNTech or the Moderna vaccine at least four months after getting a first booster. The FDA also says that individuals 12 years older who are immunocompromised or have had certain organ transplants may also be eligible for the Pfizer booster, while individuals with such health conditions who are 18 or older can get a second Moderna booster. In addition, the FDA update says people who are immunocompromised and may have already gotten four shots will be able to get a fifth. The additional booster is "especially important for those 65 and older and those 50 and older with underlying medical conditions that increase their risk for severe disease from COVID-19, as they are the most likely to benefit from receiving an additional booster dose at this time," said CDC Director Rochelle Walensky.
  • CDC still recommends older adults get second COVID vaccine three to four weeks after the first. The CDC updated its vaccine recommendations on Feb. 22 to say that an eight-week interval between shots one and two in the Pfizer and Moderna two-shot series may be optimal for some people, especially males ages 12 to 39. That’s because some studies in adolescents and young adults have shown that the “small risk of myocarditis associated with mRNA COVID-19 vaccines might be reduced and peak antibody responses and vaccine effectiveness may be increased with an interval longer than four weeks,” the agency says. However, the shorter interval (three weeks for Pfizer-BioNTech and four weeks for Moderna) between the first and second doses of the mRNA vaccines remains the recommended interval for adults 65 and older, people who are immunocompromised and others at high risk for severe disease. Myocarditis, or inflammation of the heart muscle, has been reported after vaccination but is rare, the CDC says.
  • Novavax says its vaccine is safe and effective for kids. The Novavax two-dose vaccine provides 80 percent protection against symptomatic COVID-19 infection in adolescents ages 12 to 17, according to clinical trials data the company released on Feb. 11. Novavax has already asked the FDA for an emergency use authorization for its COVID-19 vaccine. In announcing its request, Novavax officials said its clinical trials showed that the vaccine was safe and provided 90 percent protection against the coronavirus for individuals 18 and older. These trials were done before the emergence of the omicron variant. The company said the two doses of the vaccine are supposed to be administered 21 days apart. The Novavax vaccine uses a different technology than the other three vaccines now available to Americans: the mRNA Pfizer-BioNTech and Moderna vaccines, which have been fully approved by the FDA, and the Johnson & Johnson single-dose product, which is available through an EUA. The Novavax vaccine is made using small, laboratory-built pieces of the coronavirus to stimulate immunity, a more traditional approach to a vaccine than the mRNA technology. If the FDA approves the Novavax product, it would then need the go-ahead from the CDC before it could begin to be available to individuals.
  • FDA fully approves Moderna vaccine. The FDA on Jan. 31 granted full approval to Moderna's COVID-19 vaccine, making it the second FDA-approved vaccine for COVID-19 in the U.S., after Pfizer-BioNTech's product was approved in August. And on Feb. 4, a CDC panel of advisers voted to back the approval and recommended the vaccine for adults 18 and older. The roughly 204 million doses of Moderna’s vaccine that have so far been administered in the U.S. were done so under emergency use authorization. In a statement, acting FDA Commissioner Janet Woodcock, M.D., said that “for some individuals, FDA approval of this vaccine may instill additional confidence in making the decision to get vaccinated” and that the vaccine, which has the brand name Spikevax, “meets the FDA’s high standards for safety, effectiveness and manufacturing quality required of any vaccine approved for use in the United States." 

Researchers around the world have been working at record speed to develop vaccines to combat COVID-19. Less than a year after the start of the pandemic, that goal became a reality.

Two vaccines (from Pfizer-BioNTech and Moderna) have received full approval from the U.S. Food and Drug Administration (FDA) and one other (from Johnson & Johnson) is being administered under a limited emergency use authorization (EUA). This FDA designation allows access to treatments and other medical tools during a public health emergency when no other options exist.

What, exactly, is a vaccine?

A vaccine is something that helps a person build up immunity to an infectious disease. It works by intentionally introducing the body to an inactive form of a disease-causing germ, or something similar to it. This then stimulates the immune system’s production of antibodies, the proteins that help to protect the person from a future infection.

Think of it like a workout for your immune system: You’re “sending it to the gym and preparing it to be able to do something," in case it meets up with the germ in the future, explains Tony Moody, associate professor of pediatrics and immunology at the Duke University School of Medicine and a principal investigator at the Duke Human Vaccine Institute. “Essentially, what a vaccine is doing is teaching the immune system how to handle something before you actually encounter the real thing — so that, hopefully, when you do encounter the real thing, you’re able to deal with it quickly and get rid of it,” he says.

What coronavirus vaccines are available now?

The vaccines from Pfizer-BioNTech, Moderna and Johnson & Johnson (J&J) are so far the only products available to Americans. The Centers for Disease Control and Prevention (CDC) recommends the Pfizer and Moderna vaccines over the J&J vaccine single-shot version because a rare but serious blood clotting disorder has been linked to it. But J&J’s vaccine is still available for people who are “unable or unwilling to receive an mRNA vaccine,” the CDC said in a statement issued Dec. 16. 

Pfizer’s vaccine is approved for people 16 and older and is available for people ages 5-15 under emergency use authorization. Moderna's vaccine is approved for people 18 and older; J&J's product is authorized for the same age group.

The three vaccines lower your risk of getting infected with the virus and have been found to be highly effective at preventing severe illness from an infection. Hospitalizations in February 2022 were nine times higher in unvaccinated individuals ages 65 and older, compared to their vaccinated and boosted peers, federal data shows.

Are the vaccines safe?

Participants in the Pfizer-BioNTech, Moderna and Johnson & Johnson trials experienced side effects after vaccination, including injection-site pain, fever, chills, headaches, muscle aches and joint pain. These symptoms are usually mild to moderate in severity and are temporary. They are also in line with side effects that some people experience from other vaccines, including the flu shot and the vaccine to prevent shingles.

More serious reactions have occurred but are rare. Anaphylaxis, a severe allergic reaction, has happened in a small number of people after COVID vaccination, the CDC says. This is why you may be asked to wait about 15 minutes after your shot or booster to monitor for symptoms. Vaccines providers are equipped with medicines to quickly treat the reaction. 

Health officials are also monitoring rare reports of myocarditis and pericarditis in some adolescents and younger adults who have received the Pfizer and Moderna vaccines. Most of these patients who received care responded well to medicine and felt better quickly, the CDC says.

Another uncommon event that has been linked to J&J’s vaccine is a rare but serious clotting disorder, called thrombosis with thrombocytopenia syndrome. Fifty-four cases of the condition were confirmed as of August out of about 14 million doses administered; nine people have died from it. Young women in their 30s and 40s are most at risk. After reviewing evidence of the adverse event, the CDC decided on Dec. 16 to recommend Pfizer's and Moderna’s vaccines over J&J’s version; months later, the FDA limited its use. J&J’s vaccine, however, is still available to those who are “unable or unwilling” to get the Pfizer or Moderna vaccine.

How much does the vaccine cost?

The federal government pre-purchased hundreds of millions of vaccine doses with taxpayer money, so Americans do not have to pay to receive them, including the booster shots.

Vaccine providers are able to charge an administration fee for giving the shot, but this fee should be covered by public or private insurance or by a government relief fund for the uninsured.

Can I still get COVID-19 after getting the vaccine?

​Because no vaccine is 100 percent effective, breakthrough infections can occur, and more are being reported as omicron and its subvariants rip through the country. But experts stress that the vaccines and booster remain highly protective against hospitalization and death if you do catch COVID-19. 

Breakthrough infections, however, can contribute to the spread of COVID-19, which is why health officials recommend that vaccinated individuals in areas of high community transmission wear a face mask in indoor public settings.

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Do I need the vaccine if I have already had COVID-19?

Even if you had COVID-19, the CDC still recommends getting vaccinated and boosted, since research has not yet shown how long protection from a previous coronavirus infection lasts.  Plus, the vaccine may afford better protection against COVID-19 than a previous infection. Unvaccinated people who already had COVID-19 had greater odds of getting COVID-19 again, compared to fully vaccinated people, a CDC study found

Have questions? Talk to your doctor.

Is it good to have more than one vaccine available?

Absolutely. “In fact, it’s highly desirable,” says William Schaffner, an infectious disease expert and professor at Vanderbilt University School of Medicine, because that would mean “there would be more vaccine manufacturers working to actually produce the vaccine, and so we could more expeditiously try to vaccinate the population in the United States and beyond.”

Kathleen Neuzil, M.D., professor in vaccinology and director of the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, echoes Schaffner’s sentiment and points to the flu vaccine for comparison: There are multiple formulations on the market, including the injectable high-dose vaccine and the nasal spray vaccine, for example, which are recommended for different populations.

“We really need every person on Earth, theoretically, to be able to receive this vaccine. So, to me, [having more than one option] is a positive, because we need so much,” she adds.

Editor’s note: This article, originally published May 1, 2020, has been updated to reflect new information.