The politicization of COVID-19 vaccines – and almost everything to do with the pandemic – has caused confusion, and total fatigue.
And some posts circulating on social media, for example a cleverly edited piece on YouTube, seem to take advantage of these sentiments, trying to cast doubt on the effectiveness of vaccines.
This is an edit of comments by Dr. Anthony Fauci, the White House medical adviser.
It begins by highlighting vaccine protection with screenshots of news headlines, first citing 100% effectiveness, followed by another edition showing lower percentages. It ends with a montage of headlines about the profits of pharmaceutical companies, with the orchestral background “In the Hall of the Mountain King.”
But watching the video in slow motion reveals more complexity. Some headlines report studies that only looked at infection rates. Others hospitalizations and deaths.
Some even refer to vaccines that are not being used in the United States.
In short, video encourages misperceptions by mixing different data and omitting key details.
Still, one cannot help but wonder what is really going on with effectiveness.
First: no vaccine is 100% effective against any disease. Doses for COVID-19 are no exception. In some studies, efficacy in preventing infections, defining infection as a positive test result, appears to decrease dramatically the longer it takes after completing the one or two dose regimen.
But on the key measures – prevention of serious illness, hospitalization, and death – real-world studies from the United States and other countries generally show that protection weakens slightly, particularly in older or sicker people, but remains strong. , even with the spread of delta, the most infectious variant of the virus.
The essential? Getting vaccinated with any of the three vaccines available in the United States decreases the chance of becoming infected in the first place and significantly reduces the risk of hospitalization or death if you contract the coronavirus and develop Covid-19.
The Centers for Disease Control and Prevention (CDC) recently published a study showing that fully vaccinated people were 10 times less likely to die or be hospitalized than unvaccinated people.
“When it comes to what matters, vaccines hold up very well,” said Dr. Amesh Adalja, infectious disease physician and senior scholar at the Johns Hopkins Center for Health Safety. “They were designed to domesticate the virus.”
So what do “efficacy” and “effectiveness” mean?
Before federal regulators approve a drug or vaccine, it is tested in volunteers randomly assigned to receive the product or a placebo (a substance that does not have the ingredients of the original product).
The researchers then compare how the two groups are doing. In the case of a vaccine, they look at how well it prevents infection and whether it protects against serious illness, hospitalization, or death. The results of clinical trials are often called efficacy measures.
In the real world, however, the performance of a drug or vaccine is affected by many factors, including a much larger number of people who receive it, some of them with underlying conditions or socioeconomic circumstances different from those in the clinical trial. That real-world measure of performance is called effectiveness.
When licensed for emergency use after reviewing clinical trials, the Pfizer-BioNTech and Moderna two-dose vaccines reported efficacy against symptomatic diseases in an average range of 90%.
Johnson & Johnson’s one-dose vaccine, which was tested later, when there were more variants, reported an overall efficacy in the high range of 60%. Those numbers exceeded the target threshold of 50% that health officials were looking for at the very least. As a comparison, the real-world effectiveness of the annual flu vaccine is typically 40% to 50%.
Another point: 95% effectiveness does not mean that 95% of vaccinated people will never become infected. What it means is that a fully vaccinated person exposed to the virus faces only 5% of the risk of infection compared to an unvaccinated one.
Have the effectiveness figures changed?
Yes, some studies show a decrease in efficacy against infections. Some have also expressed concern that protection against the severe form of the disease may also be diminished, particularly in older people and patients with underlying medical conditions.
The reasons for the withdrawal vary.
First, when vaccines were licensed, much of the country was under stricter quarantine rules related to the pandemic. Almost a year later, restrictions, including mandates on wearing masks, have been eased in many areas. More and more people are traveling and are faced with situations that they would have avoided a year ago. So the exposure to the virus is higher.
Some studies in the United States and other countries show that the time since vaccination also plays a role.
The Lancet recently published a study of more than 3.4 million Kaiser Permanente members, both vaccinated and unvaccinated, reviewing the effectiveness of Pfizer’s vaccine. It showed an overall average effectiveness of 73% against infection during the six months after immunization, and an overall effectiveness of 90% against hospitalization.
But protection against infection decreased from 88% in the month after full vaccination to 47% between five and six months. The time since vaccination played a bigger role than any change in the virus itself, the researchers concluded.
“This shows that vaccines are highly effective over time against severe outcomes,” said report lead author Sara Tartof, an epidemiologist with the Kaiser Permanente Southern California Department of Research and Evaluation. “Against infection, it decreases over time, which is not unexpected. We have boosters for many other vaccines ”.
The virus has also mutated
“Delta is here,” said Dr. William Schaffner, professor of preventive medicine at Vanderbilt University School of Medicine. “Because this virus was so contagious, it changed the results slightly.”
And some vaccinated people can become seriously ill from covid, or even die, especially if they have an underlying medical problem, as was the case with General Colin Powell. He died of complications from covid despite being fully vaccinated, probably because he also had a blood cancer called multiple myeloma, which can reduce the body’s response to an invading virus and vaccination.
What should we do with these changing numbers and the recent authorization of booster shots?
Most scientists, researchers, and doctors say that vaccines are working very well, especially in preventing severe covid disease and death.
And it is not uncommon for more than one dose to be needed.
The shingles and measles vaccines require two shots, while people must re-vaccinate against tetanus every 10 years. Because flu varies from year to year, flu shots are yearly.
The immune response is usually best when doses are given months apart. But at the time of the vaccines’ launch, there were so many people becoming infected and dying from covid that the Food and Drug Administration (FDA) and the CDC decided not to delay, but to authorize the first and second doses about a month apart.
“We learn as we go along,” Schaffner said. “It was always anticipated that there might have to be follow-up doses.”
Now, the recommendations call for a second dose for anyone who has received a Johnson & Johnson injection at least two months prior.
For those who received the two-dose Pfizer or Moderna vaccines, the recommendation is to wait six months after the second dose to receive a booster, which is currently recommended for those 65 years of age or older; people with pre-existing conditions, who live in congregated settings such as nursing homes; or they have jobs that put them at greater risk. Booster recommendations may be expanded in the coming months.
KHN (Kaiser Health News) is the newsroom of KFF (Kaiser Family Foundation), which produces in-depth journalism on health issues. Along with Policy Analysis and Surveys, KHN is one of KFF’s top three programs. KFF is a nonprofit organization that provides health information to the nation.
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