Advisers to the US Food and Drug Administration on Friday voted unanimously to recommend emergency use authorization of Pfizer’s booster shot six months after full vaccination in Americans 65 and older as well as those at high risk of severe Covid-19.
That vote came after the group had first voted and rejected a broader application: to approve the third shot in all Americans 16 and older six months after they were fully vaccinated.
Dr. Steven Pergam, medical director for infection prevention at Seattle Cancer Care Alliance, expressed concern that the recommendation the advisers approved did not cover health care workers, who are at high risk of exposure to the virus, even if they are not necessarily at high risk of severe disease.
But the FDA can make its own decision and has asked the advisers to weigh in on possible changes in wording for the emergency use authorization, said Dr. Peter Marks, who heads the FDA’s vaccine arm. Committee members voted unanimously to informally advise the agency to include healthcare workers or others at high risk in the authorization.
The most important message for now remains to get more Americans fully vaccinated, some experts say.
“I don’t think a booster dose is going to significantly contribute to controlling the pandemic,” said Dr. Cody Meissner, a professor of pediatrics at Tufts University School of Medicine.
“It is very important that the main message that we still transmit is that we have got to get everyone two doses. Everyone has got to get the primary series.”
More than 2 million Americans have received a booster dose of a Covid-19 vaccine, according to data published Friday by the US Centers for Disease Control and Prevention.
Pfizer got strong pushback on its request Friday after saying it has data showing that immunity wanes six months or so after people are fully vaccinated with two doses, and adding that a third dose at six to eight months restores that immunity.
Dr. Phil Krause, deputy director of the FDA’s Office of Vaccines Research and Review noted Pfizer was using data that had not been reviewed by experts.
Three reports published Wednesday supporting the argument that people may need a booster dose of Pfizer’s Covid-19 vaccine over time were part of the data discussed by the FDA’s vaccine advisers.
The meeting, streamed online, began Friday morning.
Four days earlier, a group of international vaccine experts, including some from the FDA and the World Health Organization, wrote in the Lancet that current evidence does not appear to support a need for booster shots in the general public right now.
The proportion of the population that is fully vaccinated — now at around 54.4% of the entire population — is still far below where experts have said it needs to be to slow or stop the spread, and cases have been on the rise.
Disparity in the Covid-19 pandemic
The pandemic has impacted different populations differently, and people of color are bearing a heavy burden, according to new research.
Black people, those over 40 and people with pre-existing conditions were the most likely sufferers of long Covid symptoms, which impacted a third of the Covid-19 patients, according to a study by the Long Beach department of Health and Human Services in California.
The most common extended symptom was fatigue, followed by loss of taste and loss of smell, the team reported in the US Centers for Disease Control and Prevention’s weekly Morbidity and Mortality Weekly Report.
“The odds of experiencing symptoms 2 months after a positive SARS-CoV-2 test result were significantly higher among females, persons with at least one preexisting condition, and those aged 40–54 years,” they wrote.
Black people had higher rates of difficulty breathing, joint pain, and muscle pain than other racial and ethnic groups. These results show a need to monitor demographic disparities in extended Covid-19 symptoms, the researchers said.
And an analysis published Thursday by the Kaiser Family Foundation found that the race-based disparities among children mirrored those among adults.
Compared to White children, kids of color have had more cases, deaths, and have had more mental health and academic problems related to the pandemic. While the most vulnerable, they’re also less likely to be vaccinated, according to the analysis.
While Covid-19 hospitalization and death are rare among children compared to adults, those kids who were hospitalized were more likely to be Black and Hispanic. Black and Hispanic kids were also more likely to have a Covid-19-related condition called MIS-C — multisystem inflammatory syndrome in children — and Black children were more likely to be admitted to intensive care for it.
Black, Hispanic, American Indian and Alaska Native children were more likely to die from Covid-19 than White children.
“Because children make up a significant share of the population and are more racially diverse than the rest of the population, equitable vaccination among this group is key for achieving an overall high rate of vaccine coverage among the population and may help to reduce disparities in vaccination rates more broadly,” the report said.
Masks help block airborne transmission, study shows
Meanwhile, new research published this week indicates the Alpha variant of coronavirus spread more easily as people breathed or spoke but showed that even the simplest masks can greatly reduce transmission.
“Our latest study provides further evidence of the importance of airborne transmission,” said Dr. Don Milton, professor of environmental health at the University of Maryland School of Public Health, who worked on the study.
The intensive study, conducted at the University of Maryland, the Walter Reed Army Institute of Research and elsewhere, showed people expel virus in their breath and saliva — findings that support the now widely accepted idea that the virus is spread in droplets of all sizes that fall to surfaces or float in the air. They measured RNA, the genetic material most commonly used to detect virus.
Loose-fitting masks stopped about 50% of virus-laden particles from getting out, the team found.
Milton said they’re now testing to see what happens with the Delta or B.1.617.2 variant, which is far more transmissible than Alpha and which now accounts for virtually all infections in the US currently.
But the implications of the findings about Alpha are clear.
“SARS-CoV-2 is evolving toward more efficient aerosol generation and loose-fitting masks provide significant but only modest source control. Therefore, until vaccination rates are very high, continued layered controls and tight-fitting masks and respirators will be necessary,” the team wrote.
“We know that the Delta variant circulating now is even more contagious than the Alpha variant. Our research indicates that the variants just keep getting better at travelling through the air, so we must provide better ventilation and wear tight-fitting masks, in addition to vaccination, to help stop spread of the virus,” Milton said in a statement.
