Vaccine protection against Covid-19 declines over time, especially for older people, CDC says

“We’ve also seen declines, especially for Pfizer, for 65 and over, which we don’t see in younger populations. Finally, there is evidence of a decline in VE versus hospitalization in the Delta period, ”she said.

The CDC’s advisory committee on immunization practices met on Wednesday to discuss the potential need for vaccine booster doses and discuss the efficacy and safety of vaccines in general.

Pfizer has asked the United States Food and Drug Administration to approve a booster dose of its vaccine for people 65 years of age and older. The FDA’s own vaccine advisers have recommended a booster only for people 65 years of age and older, those with underlying conditions that put them at high risk of serious illness, and for people whose work puts them at risk of serious illness. high risk of exposure.

Link-Gelles said that, overall, the efficacy of Moderna’s vaccine is superior to that of the vaccine made by Pfizer / BioNTech. For the Johnson & Johnson vaccine, the effectiveness of the vaccine actually increases over time, even after the Delta variant has dominated.

A study called SUPERNOVA looked at veterans between February and August of this year. In that study, the Pfizer vaccine provided 92% protection against hospitalization for those 18 to 64 and 77% for those over 65, Link-Gelles said. The Moderna vaccine provided 97% protection against hospitalization for those aged 18-64 and 87% for those aged 65 and over. Efficiency does not appear to be affected by the arrival of the Delta variant, according to the study.

A study called IVY looked at adults hospitalized in 18 states between March and August. The effectiveness of Pfizer’s vaccine increased from 91% 14 to 120 days after full vaccination, to 77% three months or more after full vaccination. The effectiveness of Moderna’s vaccine did not significantly decrease, remaining at 92% or 93% in this study.

In a study of 4,000 healthcare workers, first responders and other frontline workers in eight locations that were tested weekly for all symptoms, vaccine protection against any infection increased from 91% before Delta to 66% during Delta.

Pfizer told ACIP that it hopes and expects antibody protection from a third dose of its Covid-19 vaccine to last longer than after the initial two doses, but more research will be needed to determine if additional doses would be needed later.

The conversation for now centers on a third dose – a booster – of the company’s two-dose Covid-19 vaccine, and experience with past vaccines suggests that a third dose may provide longer and longer protection. forte, Dr William, Senior Vice President of Pfizer. Gruber told the committee. In this case, the primary series of the vaccine may work best in three doses, Gruber noted. But, he acknowledged, some experts believe protection is likely to wane again after a third booster dose.

“I think a lot of it will depend on what we find in retrospect as we gather more information on protection, and we just need to stay tuned,” Gruber said.

Gruber also said the company would continue to explore whether a longer interval between vaccine doses would work better; currently the recommendation is 21 days between a first and second dose. He noted that researchers in Europe and elsewhere have studied longer intervals, but the company’s goal has been to maximize protection as quickly as possible during the pandemic.

“We will continue to explore whether or not it makes sense to look at a longer interval,” Gruber said.

Pfizer is not studying the use of its vaccine as a booster for Moderna or Johnson & Johnson vaccines, Gruber said, but it welcomes studies by others. Committee members asked if it was worth discussing, but CDC officials said the only data available concerned the use of a Pfizer vaccine to boost the immunity of people who had initially received the same. Pfizer vaccine.

ACIP members said they were concerned people would mistake the booster talk for a signal that Covid-19 vaccines are not working well. They agreed that this would be a mistaken impression and one that public health specialists should fight against.

But people also need to understand that coronavirus vaccines will never be able to completely defeat this virus.

“Coronaviruses often become endemic, and it is highly unlikely that we will prevent all mild or symptomatic respiratory infections,” ACIP member Dr Helen Keipp Talbot of Vanderbilt University said at the meeting.

“One of the things we have to start to understand is that we will probably avoid hospitalizations and deaths, and hopefully symptomatic lower respiratory tract infections, but we are unlikely to prevent everything,” a- he added.

The panel also heard about studies on the safety of Covid-19 vaccines in pregnant women.

“It has been incredibly reassuring so far,” Dr. Grace Lee, professor of pediatrics at Stanford University School of Medicine and ACIP President, said at the meeting.

So far, there is no evidence that getting the vaccine during pregnancy increases the risk of miscarriage or birth defects, several experts said at the meeting. Yet only 30% of pregnant women in the United States have been vaccinated against the coronavirus – even as Covid-19 kills more pregnant women than ever, advisers have heard.

And pregnant people are at a higher risk than most serious illnesses if they catch coronavirus, said Dr Dana Meaney Delman, head of maternal immunization at the CDC.

“We are now seeing an increase in the number of pregnant women admitted to intensive care in July and August,” Meaney Delman said at the meeting. The trend continued in September, she said. “The deaths reported in August are the highest number of deaths reported since the start of the pandemic,” added Meaney Delman. About 97% of pregnant women treated in hospital for Covid-19 have not been vaccinated, she said.

“I want to speak directly to the public,” added Meaney Delman. “We know that pregnant people with Covid-19 can get very sick. Some will die, and many will experience pregnancy and neonatal complications. We know that because of Covid some children will grow up without their mothers. We know that Covid-19 vaccines are safe and effective. If you are pregnant, postpartum, breastfeeding, trying to get pregnant now or could become pregnant in the future, please get vaccinated.