The latest on Covid-19 boosters in the US

New Covid-19 cases continue to fall in the United States, but more than 90% of counties – home to more than 319 million people – still have “high” or “substantial” community transmission, according to thresholds set by the US Centers for Disease Control and Prevention. 

A community is considered by the CDC to have “high” transmission if there have been 100 or more new cases per 100,000 people over the past seven days or if the test positivity rate is 10% or higher. A community is considered to have “substantial” transmission with at least 50 new cases per 100,000 people over the past week or a test positivity rate of 8% or higher. 

About two-thirds of the US population – more than 221 million people – live in a county with “high” transmission, and another 30% – about 98 million people – live in a county with “substantial” transmission, according to a CNN analysis of federal data.

At the state level, seven states are considered to have “substantial” transmission – California, Florida, Hawaii, Louisiana, Maryland, Mississippi and New Jersey – while all others are considered to have “high” transmission, CDC data shows.

In those areas with “high” or “substantial” transmission, current CDC guidance recommends universal masking in all public indoor spaces and other layered prevention strategies.

In response to a question about whether the CDC will update recommendations for fully vaccinated people as trends in community spread change, Walensky said “we’re watching that very carefully.”

“As we watch the community levels come down, we will update our recommendations,” she said. “It’s important to note that as we look at the current situation, we are also heading into respiratory virus season. During that season, we know respiratory viruses tend to thrive, and so we’re taking all of those into consideration.”

Data on the use of a Covid-19 vaccine in children ages 5 to 11 comes from a much smaller number of trial participants than the adult trials, which means having enough information is important, Dr. Paul Offit, a vaccine adviser with the US Food and Drug Administration, told CNN on Friday. 

Pfizer’s trial included around 2,000 children with twice as many children receiving the vaccine as the placebo. There were three Covid-19 cases among the group that received the vaccine and 16 cases in the placebo group.

“When you look at data for a few thousand children, you’re then about to make a recommendation for millions or tens of millions of children, and you want to make sure you have enough information to do that.” 

Offit said the advisory committee, which is scheduled to meet on Oct. 26 to discuss the use of Pfizer’s Covid-19 vaccine in children ages 5 to 11, only offers advice based on the data given to the US Food and Drug Administration. After the FDA, the US Centers for Disease Control and Prevention then has to make the full recommendation for the use of the vaccine. 

“I can promise you that when we have this discussion that if we do end up recommending this vaccine, we would only do it if we would give it to our own children,” Offit said. 

“It's true that you never know everything, the question is when do you know enough and that's going to be the question we're going to try and answer next Tuesday.”

Earlier this week, the White House unveiled its plans to roll out Covid-19 vaccines for children ages 5 to 11, pending FDA authorization.

Data so far seems to suggest that Covid-19 booster shots can help reduce the spread of coronavirus, but more research is needed to confirm that, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Friday.

In a White House virtual briefing, Fauci said data out of Israel suggests that giving fully vaccinated people booster shots can reduce transmission of the virus.

"So, although that's not definitive, it does strongly suggest that there is an impact on transmissibility," Fauci added. "But further studies would have to confirm that."

People eligible for Covid-19 vaccine booster doses should get their shots, including those who may be pregnant or nursing, Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention, said on Friday.

"You should get vaccinated if you are pregnant," Walensky added. "If you are eligible for a boost and you are pregnant, you should also get your boost during that period of time – and I would say for nursing as well."

Walgreens announced today that eligible individuals can now get Moderna and Johnson & Johnson Covid-19 vaccine booster shots in stores nationwide following new guidance from the Centers for Disease Control and Prevention late Thursday.

Some background: The director of the CDC, Dr. Rochelle Walensky, signed off Thursday on booster shots for some Americans who received the Moderna and Johnson & Johnson vaccines. Last month, she did the same for some people who have received the Pfizer vaccine.

You can find more information on eligibility and how to book an appointment here,

Booster doses of coronavirus vaccines so far seem to be as safe as first and second doses, vaccine advisers to the US Centers for Disease Control and Prevention were told Thursday.

One question the Advisory Committee for Immunization Practices (ACIP) discussed when they met Thursday was whether adding a third dose of Moderna’s vaccine or a second dose of Johnson & Johnson’s is safe.

So far, the answer is yes, Anne Hause of the CDC’s Covid-19 Vaccine Task Force told the ACIP meeting.

She reviewed data from two vaccine safety monitoring programs – the Vaccine Adverse Reporting System (VAERS) and the cellphone-based vSafe system set up to monitor Covid-19 vaccines. 

“Overall, 94% of the 4,990 adverse reports following dose two of Janssen or dose three of mRNA Covid-19 vaccinations were non-serious,” Hause said. She said rates are similar to what’s been seen for Covid vaccines in general. The most common serious adverse event was the wrong vaccine having been administered. 

“Anyone can submit a VAERS report regardless of the possibility of vaccine causing the event or the clinical seriousness of the events,” Hause noted. 

Nonetheless, few worrying reports came in.

“We did not observe any unexpected patterns of adverse events,” Hause told the meeting. “Nearly all reports to VAERS were non-serious.” Common adverse events included sore arms, headaches, fevers and muscle aches. A sore arm was considered a local event, while a fever or headache would be a systemic event.

Not many people have received a second dose of Johnson & Johnson’s Janssen Covid-19 vaccine, Dr. Helen Keipp Talbot, an associate professor of medicine at Vanderbilt University who heads one of ACIP’s safety working groups, told the meeting. The vaccine is linked with a slightly higher risk of two rare but dangerous side effects – a blood clotting condition called thrombosis with thrombocytopenia syndrome, and a neurological condition called Guillain-Barré syndrome. “There have been no new safety signals following a second dose,” Talbot told the meeting.

US Centers for Disease Control and Prevention Director Dr. Rochelle Walensky endorsed recommendations for booster doses for Moderna’s and Johnson & Johnson’s coronavirus vaccines Thursday evening, clearing the way for millions more Americans to get booster shots. Some adults were already eligible to get booster shots of Pfizer’s Covid-19 vaccine.

Currently Pfizer’s and Moderna’s Covid-19 boosters are authorized for those 65 and older as well as those 18 and older who live in long-term care settings, have underlying medical conditions or who work or live in high-risk settings. 

A booster of Johnson & Johnson is recommended two months after vaccination for everyone 18 and older.

While speaking to NBC’s "Today" Friday morning, Walensky was asked about expanding booster eligibility to people as young as 40. 

Asked by NBC’s Savannah Guthrie if those who fell outside of the eligible categories should be worried about waning immunity, Walensky said “I don’t think that there’s reason to be concerned now.” She added “Our vaccines are still working really well against severe disease, hospitalization and death.

Walensky also recommended that people follow prevention measures as there is “a lot of disease out there.” She said the CDC will continue to follow any data that demonstrates if and when there is waning protection for people who are generally healthy. 

In new documents posted ahead of a key meeting of the US Food and Drug Administration’s vaccine advisers, Pfizer says its vaccine is safe and 90.7% effective against symptomatic Covid-19 in children ages 5 to 11.

In the trial, which included around 2,000 children, there were three Covid-19 cases among the group that received the vaccine and 16 cases in the placebo group. In the trial, twice as many children received the vaccine as the placebo.

Pfizer/BioNTech are seeking FDA emergency use authorization (EUA) of a two-dose regimen of their 10-microgram dose for children ages 5 to 11. The two doses would be administered three weeks apart.

Last month, Pfizer released details of a Phase 2/3 trial that showed its Covid-19 vaccine was safe and generated a "robust" antibody response in children ages 5 to 11. The trial included 2,268 participants ages 5 to 11. Participants' immune responses were measured by looking at neutralizing antibody levels in their blood and comparing those levels to a control group of 16- to 25-year-olds who were given a two-dose regimen with the larger 30-microgram dose. Pfizer said the levels compared well with older people who received the larger dose, demonstrating a "strong immune response in this cohort of children one month after the second dose."

The FDA’s Vaccines and Related Biological Products Advisory Committee is scheduled to meet Oct. 26 to discuss whether to recommend the vaccine for authorization for those ages 5 to 11.

If authorized, this would be the first Covid-19 vaccine for younger children. The Pfizer/BioNTech vaccine is approved for people age 16 and older and has an EUA for people ages 12 to 15.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told CNN’s John Berman that while it makes sense to get a booster shot that is the same as the original vaccine series, it’s also OK to mix and match. 

Some background: US Centers for Disease Control and Prevention Director Dr. Rochelle Walensky endorsed recommendations for booster doses for Moderna’s and Johnson & Johnson’s coronavirus vaccines Thursday evening, which cleared the way for millions more Americans to get booster shots. Some adults were already eligible to get booster shots of Pfizer’s Covid-19 vaccine.