CDC Panel Unanimously Backs Pfizer Vax, Fortifying FDA Approval

Brenda Goodman, MA

August 30, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

An independent expert panel within the Centers for Disease Control and Prevention (CDC) has studied the potential benefits and risks of the Pfizer-BioNTech COVID-19 vaccine and voted unanimously to recommend the shots for all Americans ages 16 and older.

All 14 members of the Advisory Committee on Immunization Practices (ACIP) voted 'yes' to recommend the vaccine for Americans ages 16 and up. The vaccine was fully approved by the US Food and Drug Administration (FDA) last week.

The inoculation is still available to teens ages 12 to 15 under an emergency use authorization from the FDA.

ACIP now sends its recommendation to the CDC Director Rochelle Walensky, MD, for her sign off.

After reviewing the evidence behind the vaccine, panel member Sarah Long, MD, a professor of pediatrics at Drexel University College of Medicine, Philadelphia, Pennsylvania, said she couldn't recall another instance where panelists had so much data on which to base their recommendation.

"This vaccine is worthy of the trust of the American people," she said.

Doctors across the country use vaccines in line with the recommendations made by the ACIP. Their approval typically means that private and government insurers will cover the cost of the shots. In the case of the COVID-19 vaccines, the government is already picking up the tab.

Few Surprises

The panel's independent review of the vaccine's effectiveness from nine studies held few surprises. 

They found the Pfizer vaccine prevented a COVID infection with symptoms about 90%–92% of the time, at least for the first 4 months after the second shot. Protection against hospitalization and death was even higher.

The vaccine was about 89% effective at preventing a COVID infection without symptoms, according to a pooled estimate of five studies.

The data included in the review was only updated through March 13 of this year, however, and does not reflect the impact of further waning of immunity or the impact of the Delta variant.

In making their recommendation, the panel got an update on the safety of the vaccines, which have now been used in the US for about 9 months.

The rate of serious allergic reactions, called anaphylaxis, has settled at around five cases for every million shots given, according to the ACIP's review of the evidence. 

Cases of myocarditis and pericarditis, serious inflammation of the heart after vaccination, were more common after getting a Pfizer-BioNTech vaccine than would be expected to happen naturally in the general population, but the risk was still very rare, and elevated primarily for men younger than age 30. 

Out of 17 million second doses of Pfizer-BioNTech vaccines in the US, there have been 327 confirmed cases of myocarditis reported to the Vaccine Adverse Event Reporting System in people who are younger than age 30. The average hospital stay for a myocarditis cases is 1 to 2 days. 

So far, no one in the US diagnosed with myocarditis after vaccination has died.

What's more, the risk of myocarditis after vaccination was dwarfed by the risk of myocarditis after a COVID infection. The risk of myocarditis after a COVID infection was 6 to 34 times higher than the risk after receiving an mRNA vaccine.

The CDC said they’d like to have more data on long term outcomes after myocarditis, so they’re going to start following people who’ve experienced the side effect to see how they fare months later.

About 11% of people who get the vaccine experience a serious reaction to the shot, compared with about 3% in the placebo group. Serious reactions were defined as pain; swelling or redness at the injection site that interferes with activity; needing to visit the hospital or ER for pain; tissue necrosis, or having skin slough off; high fever; vomiting that requires hydration; persistent diarrhea; severe headache; or muscle pain/severe joint pain.

"Safe and Effective"

After hearing a presentation on the state of the pandemic in the US, some panel members were struck and shaken that 38% of Americans who are eligible are still not fully vaccinated.

Pablo Sanchez, MD, a pediatrician at Nationwide Children's Hospital in Columbus, Ohio, said, "We're doing an abysmal job vaccinating the American people. The message has to go out that the vaccines are safe and effective."

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