The Centers for Disease Control and Prevention released three studies Wednesday that federal officials say have provided evidence that booster shots of the Pfizer-BioNTech and Moderna coronavirus vaccines would be needed in the coming months.
But some experts said the new research didn’t support the decision to recommend booster shots for all Americans.
Taken together, the studies show that while the vaccines remain highly effective against hospitalizations and deaths, the bulwark they provide against infection with the virus has weakened in recent months.
The finding matches early data from seven states, collected this week by NewsMadura, and suggests an increase in breakthrough infections and a smaller increase in hospitalizations among those vaccinated as the Delta variant spread in July.
The decline in effectiveness against infection could be the result of declining vaccine immunity, the lapse of precautions like wearing masks or the emergence of the highly contagious Delta variant, experts said — or a combination of all three.
“We are concerned that this pattern of decline we are seeing will continue in the coming months, which could lead to reduced protection against major illness, hospitalization and death,” said Dr. Surgeon General Vivek Murthy during a White House press conference. on Wednesday.
Citing the data, federal health officials outlined a plan for Americans who received the two vaccines to receive booster shots eight months after receiving their second doses, beginning Sept. 20.
People who have received the Johnson & Johnson vaccine may also need additional doses. But that vaccine wasn’t rolled out until March 2021, and a plan to provide boosters will be made after reviewing new data expected in the coming weeks, officials said.
Some scientists were skeptical of the government’s new initiative.
“These data support administering additional vaccine doses to individuals with high immune systems and nursing home residents, not the general public,” said Dr. Céline Gounder, an infectious disease specialist at the Bellevue Hospital Center and a former consultant on the administration’s pandemic.
Boosters would only be justified if the vaccines didn’t prevent Covid-19 hospitalizations, she said.
“Feeling sick like a dog and lying in bed but not in the hospital with severe Covid is not a good reason” for a campaign of booster shots, said Dr. gounder. “We will be better protected by vaccinating the unvaccinated here and around the world.”
It’s unclear whether a third dose would help people who didn’t produce a robust immune response to the first two doses, said Bill Hanage, an epidemiologist at Harvard’s TH Chan School of Public Health.
And the recommendation for boosters could also ultimately undermine confidence in the vaccines, he warned: “A third injection will add to skepticism in people who receive another dose that the vaccines help them.”
Together, the new studies indicate that vaccines have approximately 55 percent effectiveness against all infections, 80 percent against symptomatic infection and 90 percent or more against hospitalization, noted Ellie Murray, an epidemiologist at Boston University.
“Those numbers are actually really good,” said Dr. Murray. “The only group for which these data would suggest boosters is, to me, the immunocompromised.”
The apparent reduction in vaccine effectiveness against infection could instead have been caused by increased exposure to the highly contagious Delta variant during a period of unimpeded social interactions, she added: “This seems to me a real possibility, as many early vaccinees were motivated by a desire to see friends and family and return to normal.”
dr. Murray said a booster shot would undoubtedly boost a person’s immunity, but the added benefit may be minimal — and just as easily obtained by wearing a mask or by avoiding indoor dining and crowded bars.
The government’s emphasis on vaccines has undermined the importance of building other precautions into people’s lives in a way that is comfortable and sustainable, and of increasing testing capacity, said Dr. Murray and other experts.
“This is one of the reasons I think the government’s focus on vaccines is so damaging to morale,” she added. “We probably won’t go back to normal anytime soon.”
Before people can get boosters, the Food and Drug Administration must first approve a third dose of the vaccines made by Pfizer-BioNTech and Moderna, and a CDC advisory committee must review the evidence and make recommendations.
One of the new CDC studies analyzed the effectiveness of vaccines in residents of nearly 4,000 nursing homes from March 1 to May 9, before the emergence of the Delta variant, and nearly 15,000 nursing homes from June 21 to August 1, when the variant developed new infections. dominated. in the country.
The vaccine’s effectiveness at preventing infections dropped from about 75 percent to 53 percent between those dates, the study found. It has not evaluated the protection of the vaccines against serious diseases.
Nursing homes were not required to report the number of residents immunized until after June 6, which “makes comparisons over time very challenging,” said Dr. Murray. “It is entirely possible that the vaccine effectiveness reported here has not declined over time.”
Understand the State of Vaccine and Mask Mandates in the US
- Mask Rules. The Centers for Disease Control and Prevention recommended in July that all Americans, regardless of vaccination status, wear masks in indoor public places in areas with outbreaks, a reversal of the guidance it offered in May. Find out where CDC guidelines apply and where states have their own masking policies. The battle over masks has become controversial in some states, with some local leaders defying state bans.
- Vaccine rules. . . and Buselessness. Private companies are increasingly mandating coronavirus vaccines for employees, taking different approaches. Such mandates are permitted by law and have been confirmed in court proceedings.
- College and universities. More than 400 colleges and universities are demanding that students be vaccinated against Covid-19. Almost all of them are in states that voted for President Biden.
- schools. On August 11, California announced that teachers and staff at both public and private schools should be vaccinated or tested regularly, the first state in the nation to do so. A survey published in August found that many U.S. parents of school-aged children are opposed to mandatory vaccines for students, but were more in favor of mask mandates for students, teachers and staff who have not received their injections.
- Hospitals and Medical Centers. Many hospitals and major health systems require workers to receive a Covid-19 vaccine, citing the increasing caseload fueled by the Delta variant and persistently low vaccination coverage in their communities, even within their workforce.
- New York. On August 3, New York City Mayor Bill de Blasio announced proof of vaccination would be required from employees and customers for indoor meals, gyms, performances and other indoor settings, becoming the first U.S. city to require vaccines for a wide variety of activities. . City hospital employees should also receive a vaccine or be tested weekly. Similar rules apply to employees in New York State.
- At the federal level. The Pentagon announced it would aim to make coronavirus vaccinations mandatory for the country’s 1.3 million active-duty troops “by mid-September.” President Biden announced that all civilian federal employees would be required to be vaccinated against the coronavirus or undergo regular testing, social distancing, mask requirements and restrictions on most travel.
The decrease in effectiveness may also be due to the spread of the Delta variant, said Dr. gounder.
“It makes sense to give an extra dose of vaccine to vaccinated nursing home residents, but what will have an even greater impact on protecting those nursing home residents is vaccinating their caregivers,” she said. Many health workers in long-term care facilities remain unvaccinated.
A second study evaluated data from New York State from May 3 to July 25, when the Delta variant grew and accounted for more than 80 percent of new cases. The effectiveness of vaccines in preventing adult cases dropped from 91.7 percent to 79.8 percent during that time, the study found. But the vaccines remained just as effective at preventing hospitalizations.
In those weeks, New York recorded 9,675 breakthrough infections — about 20 percent of the total number of cases in the state — and 1,271 hospitalizations among vaccinated people, accounting for 15 percent of all Covid-19 hospitalizations.
Although fully immunized people of all ages became infected with the virus, vaccine efficacy fell the most, from 90.6 percent to 74.6 percent, in people aged 18 to 49 — who are often the least likely to take precautions. and have the best chance of socializing.
Data from Israel have suggested that immunity to infection has declined in vaccinated adults aged 65 or older. But in the New York data, the effectiveness of the vaccines in that group barely budged.
Adults 65 years of age or older were more likely to be hospitalized than other age groups, regardless of vaccination status. But the vaccines showed no decrease in effectiveness against hospitalizations in any of the age groups.
The CDC’s third study found the vaccines were 90 percent effective against hospitalizations in the country, “which is excellent,” noted Dr. Gounder up.
The vaccines were less protective against hospitalization in immunocompromised people. “But not all immunocompromised individuals will respond to an additional dose of vaccine,” noted Dr. Gounder up.
To protect these vulnerable individuals, everyone around them should be vaccinated and continue to wear masks, she added.
The vaccines may appear less effective than in the studies that led to their approval, because those studies were conducted before the emergence of the Delta variant.
Statistically, the vaccines may appear to lose their relative effectiveness as more unvaccinated people become infected, recover and gain natural immunity. And scientists always expected that as more people were vaccinated, the proportion of vaccinated people among those infected would rise.
If preventing infection is the goal, it would be wiser to develop a nasal spray vaccine booster, which is better at inducing immunity in the nose and throat, where the virus enters the body, said Dr. gounder.