Moderna Vaccine's Protection Does Not Wane After 6 Months: Report

THURSDAY, Aug. 5, 2021 (HealthDay News) -- Moderna Inc. announced on Thursday that the potency of its vaccine does not dim in the first six months after the second dose.

The news came in a statement that contained little actual data, but the findings may comfort the 63 million Americans who have received two doses of the Moderna vaccine as the highly contagious Delta variant rips through swaths of the country where vaccination rates are low.

Moderna's report came from a new analysis of its ongoing clinical trial, which started in late July 2020 and recruited 30,000 volunteers. Last November, the company announced that the vaccine had an impressive efficacy of 94.1 percent. That effectiveness didn't drop much after six months, the company reported Thursday.

"We are pleased that our COVID-19 vaccine is showing durable efficacy of 93 percent through six months, but recognize that the Delta variant is a significant new threat so we must remain vigilant," Moderna CEO Stéphane Bancel said in the statement.

However, it wasn't clear whether the trial data extended into more recent months when the Delta variant became dominant, the Times reported.

In June, Moderna detailed an experiment in which its researchers tested antibodies from people who received their vaccine against the Delta variant. They found the antibodies were moderately less effective at blocking the variant from infecting cells.

Last week, Pfizer reported that its vaccine's durability also held up after six months. The vaccine's efficacy started at 96.2% for the first two months after the second dose, and dropped to 83.7 percent at six months.

The FDA is expected to give full approval to the Pfizer vaccine in September. Moderna filed for final approval of its vaccine on June 1, and expects to complete its submission in August, the Times reported.

Moderna said in its statement Thursday that in lab experiments of human blood cells, booster shots increased the number of coronavirus antibodies, suggesting that if its vaccine does weaken in future months, a booster would shore up protection. Moderna's clinical trials have also shown robust antibody responses after booster shots, the company added.

Full approval of Pfizer vaccine could come in September

The U.S. Food and Drug Administration is speeding up its timetable for full approval of the Pfizer coronavirus vaccine, hoping to complete the process by early September.

President Joe Biden said last week that he expected a fully approved vaccine in early fall, but the FDA's unofficial deadline is Labor Day or sooner, according to multiple people familiar with the plan, The New York Times reported. The agency said in a statement that its leaders recognized that full approval might counter vaccine hesitancy and had "taken an all-hands-on-deck approach" to completing full approval.

The move could help boost vaccination rates at a moment when the highly transmissible Delta variant is driving up the number of new cases across the country.

A number of universities and hospitals, the Defense Department and at least one major city, San Francisco, are expected to mandate vaccines once one is fully approved. Final approval could help clarify legal issues about mandates, the Times reported.

Federal regulators have been under growing public pressure to fully approve Pfizer's vaccine ever since the company filed its application on May 7.

"I just have not sensed a sense of urgency from the FDA on full approval," Dr. Ashish Jha, dean of the Brown University School of Public Health in Rhode Island, told the Times on Tuesday. "And I find it baffling, given where we are as a country in terms of infections, hospitalizations and deaths."

Moderna, the second most widely used vaccine in the United States, filed for final approval of its vaccine on June 1. But the company is still submitting data and has not said when it will finish, the Times reported. Johnson & Johnson, the third vaccine authorized for emergency use, has not yet applied for full approval, but plans to do so later this year.

Although 192 million Americans — 58 percent of the total population and 70 percent of the nation's adults — have received at least one shot, many Americans remain vulnerable, data from the U.S Centers for Disease Control and Prevention show. The country is averaging nearly 86,000 new infections a day, an increase of 142 percent in just two weeks, according to a Times database.

Full approval for a vaccine typically requires the FDA to review hundreds of thousands of pages of documents — roughly 10 times the data required to authorize a vaccine on an emergency basis. The agency can usually complete a priority review within six to eight months and was already working on an expedited timetable for the Pfizer vaccine, the Times reported.

What are regulators looking for? They want to see real-world data on how the vaccine has been working since they authorized it for emergency use in December, the Times reported. That means verifying the company's data on vaccine efficacy and immune responses, reviewing how efficacy or immunity might wane, examining new infections in clinical trial participants, reviewing adverse reactions and inspecting manufacturing plants. Officials have said the government is also tracking breakthrough infections among tens of thousands of vaccinated people.

At the same time, senior officials at the FDA and other agencies are debating whether at least some people who are already vaccinated will need booster shots. Senior administration officials increasingly believe that vulnerable populations like those with compromised immune systems and older people will need them, the Times reported.

A decision to fully approve Pfizer's vaccine will give doctors more freedom to prescribe additional shots for certain Americans, including those with weakened immune systems, the Times reported.

Roughly 3 percent of Americans — or about 10 million people — have compromised immune systems as a result of cancer, organ transplants or other medical conditions, according to the CDC. While studies indicate that the vaccines work well for some, other people do not produce enough of an immune response to protect them from the actual virus.

More information

The U.S. Centers for Disease Control and Prevention has more on COVID-19.

SOURCES: The New York Times; Associated Press