New data given to a CDC committee gave fresh evidence that the Covid-19 vaccination immunizations provided significant protection against severe disease until July when the Delta version of the coronavirus had spread widely throughout the United States.
Scientists also confirmed that the Pfizer-BioNTech and Moderna injections increase the risk of heart problems in younger men, but that the benefits outweighed the dangers.
According to the data, all three vaccines used in the United States remained very efficient at avoiding hospitalizations from April until July, when Delta became dominant.
The shots were at least 94 percent efficient in reducing hospitalizations in persons under the age of 75, a number that has stayed consistent for months, according to Dr. Oliver. In July, hospitalization protection for persons 75 and older fell somewhat but remained above 80%.
“Covid-19 vaccination continue to provide excellent protection against severe disease, hospitalization, and death,” stated Dr. Oliver.
However, protection against infection or mild sickness appears to have weakened in recent months. “Both declining over time and the Delta variant are plausible factors for reduced effectiveness,” she stated.
The findings come amid an ongoing debate about the need for the timing of booster doses. On August 18, health officials suggested that adults who received either the Pfizer or Moderna vaccines have a third dosage eight months following the first. If the Food and Drug Administration approves the booster doses, they will be available beginning September 20, according to top government health officials.
The recommendation is based on studies indicating that immunizations may become less effective over time at protecting against infection and mild illness. However, the shots continue to be effective against serious sickness and death, and many scientists have challenged the idea for booster doses, claiming that it is not yet evident that they are required.
At a meeting in September, the C.D.C. advisory group will analyze more evidence on the safety, effectiveness, and potential need for booster doses.
Dr. Oliver, on the other hand, believes that providing vaccination to unvaccinated people should remain the first priority: “Planning for the delivery of booster doses to vaccinated individuals should not discourage outreach for delivery of primary series to unvaccinated individuals.”
The committee unanimously recommends that Americans over the age of 16 receive the Pfizer-BioNTech vaccine, which was approved by the Food and Drug Administration last week.
In addition, researchers published fresh data on the risks of two heart disorders following vaccination: myocarditis, an inflammation of the heart muscle, and pericarditis, an inflammation of the membrane that surrounds the heart.
According to the research, the adverse effects are usually modest and transient. According to fresh statistics presented Monday at a meeting of an independent advisory committee to the C.D.C., for every million doses of the second shot given to 12- to 39-year-olds, there were 14 to 20 more occurrences of cardiac issues.
However, even for people in the greatest risk groups, Covid-19 vaccination provide significant benefits. According to a C.D.C. scientist’s estimate published on Monday, every million doses of the Pfizer vaccine delivered to 16- and 17-year-old males is predicted to produce 73 cases of heart issues while averting more than 56,000 Covid-19 cases and 500 related hospitalizations.
According to a study published last week in the New England Journal of Medicine, the risk of myocarditis was significantly higher after virus infection than after Covid-19 vaccination.
