Pfizer COVID Vaccine Shows Mettle Against Brazilian Variant

TUESDAY, March 9, 2021 (HealthDay News) -- Pfizer's coronavirus vaccine does successfully neutralize the more contagious P.1 variant of the virus recently discovered in Brazil, new research shows.

Pfizer and its German partner BioNTech conducted the study with scientists from both companies and researchers from the University of Texas Medical Branch. Blood samples from vaccinated individuals were tested against an engineered version of the Brazilian variant, the Washington Post reported. The samples came from participants in late-stage trials for the vaccine and were taken between two to four weeks after they received their second dose.

In the lab, the vaccine worked as well against the Brazilian variant as it did against the original virus, the Post reported. Last year, the vaccine showed 95 percent efficacy against the less contagious coronavirus strain. The findings were published March 8 in the New England Journal of Medicine.

Earlier research from British and Brazilian scientists that has not been peer-reviewed suggested that P.1 was more contagious and better able to evade vaccines than previous versions of the virus, the Post reported. The newer variant was first detected in January and has since spread from the Amazonian city of Manaus to multiple countries, including the United States.

In the United States, 15 cases of the Brazilian variant have been reported in nine states, according to the U.S. Centers for Disease Control and Prevention. That is far less than the 3,037 cases of the British variant that have been reported in 49 states so far.

As for vaccinations, more than 60 million Americans have gotten one shot and nearly 31.5 million people are now fully vaccinated, according to the CDC.

Another recent study on the P.1 variant, from researchers in Sao Paulo and at Washington University's School of Medicine in St. Louis, discovered that the vaccine developed by Chinese drugmaker Sinovac was ineffective against P.1, raising alarm bells.

The study, a preprint posted online last week, tested the convalescent plasma of eight individuals immunized with Sinovac's CoronaVac injection, which uses inactivated virus to stir an antibody response. The plasma samples failed to effectively neutralize the variant, researchers said.

New CDC guidelines give vaccinated Americans more freedom

New social distancing guidance released by the federal government on Monday gives fully vaccinated Americans more freedom to socialize and move through their communities.

The U.S. Centers for Disease Control and Prevention said people who are two weeks past their final shot can safely visit indoors with unvaccinated members of a single household at low risk of severe disease without wearing masks or social distancing. That recommendation would free many vaccinated grandparents who live near their unvaccinated children and grandchildren to gather for the first time since the pandemic began a year ago.

The CDC also said fully vaccinated people can gather indoors with those who are also fully vaccinated, and they do not need to be quarantined or tested after exposure to COVID-19.

"We know that people want to get vaccinated so they can get back to doing the things they enjoy with the people they love," CDC Director Dr. Rochelle Walensky said in an agency news release. "There are some activities that fully vaccinated people can begin to resume now in their own homes. Everyone – even those who are vaccinated – should continue with all mitigation strategies when in public settings. As the science evolves and more people get vaccinated, we will continue to provide more guidance to help fully vaccinated people safely resume more activities."

Some restrictions were still advised, even for the vaccinated. For example, if a vaccinated person lives in a group setting and is around someone with COVID-19, he or she should still stay away from others for 14 days and get tested, even without symptoms.

Peter Hotez, co-director of the Texas Children's Center for Vaccine Development, welcomed the new guidelines, but added they have been too long in coming.

"The sooner we move to telling people if you're fully vaccinated, you don't have to wear masks -- that will be an incentive for people to get vaccinated," Hotez told the Washington Post.

Other experts agreed.

"I'm disappointed this was not done sooner," said Monica Gandhi, an infectious disease expert at the University of California, San Francisco. As a clinician, she said she has been bombarded with questions from patients about what they can and cannot do. Recently, to console a profoundly depressed patient, she told him it was safe for both of them to take off their masks and hug. "I sat with him and looked him in the face," she recalled. "It meant a lot to him."

The level of caution people need to exercise should be determined by the characteristics of those who are unvaccinated in a social setting, the CDC said. For instance, if a fully vaccinated person visits an unvaccinated friend who is 70, and therefore at risk of severe disease, the visit should also take place outdoors, with masks and physical distancing, the guidance says.

Advocates for older people embraced the new guidance, because many older people, especially those who live alone, have spent the past year in virtual isolation, they said.

Bill Walsh, vice president for communications for AARP, said that, "To the extent this allows people, grandkids, families, loved ones in nursing homes or assisted living [to interact], we welcome that," he added. "We've heard over the past year some heart-wrenching stories of family separation."

A global scourge

By Tuesday, the U.S. coronavirus case count passed 29.1 million while the death toll passed 525,000, according to a Times tally. On Tuesday, the top five states for coronavirus infections were: California with over 3.6 million cases; Texas with nearly 2.7 million cases; Florida with over 1.9 million cases; New York with over 1.7 million cases; and Illinois with more than 1.2 million cases.

Curbing the spread of the coronavirus in the rest of the world remains challenging.

In India, the coronavirus case count was over 11.2 million by Tuesday, a Johns Hopkins University tally showed. Brazil had over 11 million cases and more than 266,000 deaths as of Tuesday, the Hopkins tally showed.

Worldwide, the number of reported infections passed 117.2 million on Tuesday, with more than 2.6 million deaths recorded, according to the Hopkins tally.

More information

The U.S. Centers for Disease Control and Prevention has more on the new coronavirus.

SOURCES: The New York Times; Washington Post; CNN