Anecdotes tell us what the data can’t: People who have been vaccinated seem to catch the coronavirus at a surprisingly high rate. But it is not known exactly how often, nor the likelihood that they will transmit the virus to other people.
Although it is clear that vaccination still provides strong protection against the virus, there is a growing concern that vaccinated people may be at greater risk of serious illness than previously thought.
There is a dearth of scientific studies with concrete answers, leaving policy makers and corporate executives to craft plans based on fragmented information. While some are renewing mandates for masks or delaying office reopening, others have cited a lack of clarity to justify staying on course. Everything can seem like a mess.
“We have to be humble about what we know and what we don’t know,” said Tom Frieden, former director of the Centers for Disease Control and Prevention and director of the nonprofit Resolve to Save Lives. “There are some things we can say for sure. The first is that this is a difficult question to answer.”
Without clear public health messages, vaccinated people are left confused about how to protect themselves. Their vulnerability is a key variable not only for public health officials trying to figure out, for example, when booster injections might be necessary, but also to inform decisions about whether to reverse reopenings amid a new wave of the virus. On a smaller scale, the unknown has left music fans unsure if it’s a good idea to watch a concert and sparked a new round of criticism from parents questioning what the school was like.
Instead of answers, a slew of case studies have emerged that present somewhat different pictures of superinfection. Variables, including when the surveys were conducted, whether a delta variable was present, how many populations were vaccinated, and even what the weather looked like at the time, make it difficult to compare results and patterns of uncertainty. It’s hard to tell which data could ultimately have more weight.
“We obviously have more progress now,” said Monica Gandhi, an infectious disease expert at the University of California, San Francisco. “We all know someone who has one. But we don’t have much clinical data.”
One of the most famous outbreaks of the disease among vaccinated people occurred in a small coastal town in Provincetown, Massachusetts, when thousands of vaccinated and unvaccinated people gathered on dance floors and at house parties the weekend of July 4 to celebrate the holiday, and what seemed like a point turnaround in the epidemic. About three-quarters of the 469 infections occurred among vaccinated people.
The authors of the Centers for Disease Control and Prevention (CDC) case study said this could mean they are just as likely to transmit Covid-19 as the unvaccinated. However, they cautioned that as more people receive the vaccination, they naturally also account for a higher proportion of Covid-19 infections, and this study was not enough to draw any conclusions. The incident prompted the CDC to retract a recommendation it issued just weeks ago and once again urged those who have been vaccinated to disguise themselves in certain places.
However, the particular details of that group of cases may have made this outbreak particularly bad, according to Gandhi.
He said in an email: “The prevalence of mild symptoms in this population was higher due to a lot of activity indoors (including privacy), weekend rain, less time outdoors, and a mixture of people with different vaccination statuses.” “.
Meanwhile, a much larger case study recently published by the Centers for Disease Control and Prevention (CDC) of infections in New York state found that the number of superbugs has been rising steadily since May, accounting for nearly 4% of cases in mid-May. July. These researchers cautioned that factors such as reduced public health restrictions and an increase in the highly contagious delta variant could influence the results.
Another CDC case study, in Colorado, found that the infection rate in one county, Mesa, was significantly higher than the rest of the state, at 7% versus about 5%. The report indicated that it may have been because the delta variant was more widely prevalent there, but also indicated that the ages of patients in Mesa and the lower vaccination rate may have played a role.
The research conducted in Israel appears to support the idea that protection from serious illness decreases in the months following vaccination, and more recently, advanced cases can eventually lead to an increase in hospitalizations. The information is preliminary and cases of serious breaches are still rare, but it reinforces the case that some people will need booster injections in the coming months.
Case studies and data from some US states have similarly shown an increase in hacking cases over time. But with the delta variant also rising, it’s hard to know if low immunity to any type of coronavirus infection is the cause, or whether the vaccines are not particularly effective against the delta variant. It can be both of course. Changing behavior among vaccinated people could also be a factor, as they return to social gatherings, travel and eat indoors.
That said, there are some facts that are well established at this point. People who are vaccinated and infected with the virus are less likely to go to hospital, need intubation, and are less likely to die from the disease. There is no doubt that vaccines provide great protection. But a large percentage of the nation — nearly 30% of American adults — has not been vaccinated, a fact that has conspired with a highly contagious delta variant to propel the country into a new wave of outbreaks.
“The big picture here is that vaccines are working and the reason for the increase in the United States is that we have very few vaccines,” Frieden said.
To some extent, revolutionary cases of any virus are to be expected. In clinical trials, no vaccine for Covid has been 100% effective – even the best vaccines have never been. The more the virus spreads, the higher the risk of breakouts. It is also common for some aspects of viral immunity to naturally decrease over time.
At the moment, there are more questions than answers. Are penetrating injuries increasing due to delta variant, decreased immunity, or a return to normal life? Are vaccinated people more likely to develop serious illnesses than previously thought? How common are super infections? It’s anyone’s guess.
“Overall, we should make public health decisions based on incomplete data,” Frieden said. “But there are many things we don’t know.”
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