Vaccinated people appear to be getting the coronavirus at a surprisingly high rate but exactly how often isn’t clear, nor is it certain how likely they are to spread the virus to others, NDTV reported.
Though it is evident vaccination still provides powerful protection against the virus, there’s growing concern that vaccinated people may be more vulnerable to serious illness than previously thought, the report said.
It said that there is a dearth of scientific studies with concrete answers, leaving public policy makers and corporate executives to formulate plans based on fragmented information. While some are renewing mask mandates or delaying office reopenings, others cite the lack of clarity to justify staying the course.
“We have to be humble about what we do know and what we don’t know,” the report quoted Tom Frieden, a former director of the Centers for Disease Control and Prevention and the head of the nonprofit Resolve to Save Lives, as saying. “There are a few things we can say definitively. One is that this is a hard question to address.”
What has emerged is a host of case studies providing somewhat different pictures of breakthrough infections. Variables including when the surveys were conducted, whether the delta variant was present, how much of the population was vaccinated and even what the weather was like at the time make it hard to compare results and suss out patterns.
“It’s quite clear that we have more breakthroughs now,” said Monica Gandhi, an infectious disease expert at the University of California, San Francisco. “We all know someone who has had one. But we don’t have great clinical data.”
One of the best known outbreaks among vaccinated people occurred in the small beach town of Provincetown, Massachusetts, as thousands of vaccinated and unvaccinated alike gathered on dance floors and at house parties over the Fourth of July weekend to celebrate the holiday — and what seemed like a turning point in the pandemic. About three-fourths of the 469 infections were among vaccinated people.
A newly released, far larger CDC case study of infections in New York state has found that the number of breakthrough infections has steadily ticked up since May, accounting for almost 4% of cases by mid-July. Those researchers cautioned that factors such as easing public health restrictions and the rise of the highly contagious delta variant might impact the results.
Yet another CDC case study, in Colorado, found that the breakthrough infection rate in one county, Mesa, was significantly higher than the rest of the state, at 7% versus about 5%. The report suggested it was perhaps because the delta variant was circulating more widely there, but also noted the ages of patients in Mesa and the lower vaccination rate may have played a role.
Case studies and data from some states in the U.S. have similarly shown an increase in breakthrough cases over time. But with the delta variant also on the rise, it’s difficult to tell whether waning immunity to any type of coronavirus infection is to blame, or if the vaccinations are particularly ineffective against the delta variant.
All that said, some facts are well established at this point. Vaccinated people infected with the virus are much less likely to need to go to the hospital, much less likely to need intubation and much less likely to die from the illness, the report said.
There’s no doubt that vaccines provide significant protection. But a large proportion of the nation — almost 30% of U.S. adults — have not been vaccinated, a fact that has conspired with the highly contagious delta variant to push the country into a new wave of outbreaks, it said.
“The big picture here is that the vaccines are working and the reason for the spike in the U.S. is we have too little vaccine uptake,” Frieden said.
To a certain extent, breakthrough cases of any virus are expected. In clinical trials, no Covid vaccine was 100% effective — even the best vaccines never are. The more the virus is in circulation, the greater the risk of breakthrough cases. It’s also common for some aspects of viral immunity to naturally wane over time.
For the time being, there are simply more questions than answers. Are breakthrough infections ticking up because of the delta variant, waning immunity or a return to normal life? Are vaccinated people more vulnerable to severe illness than previously thought? Just how common are breakthrough infections? It’s anyone’s guess.
“It is generally the case that we have to make public health decisions based on imperfect data,” Frieden said. “But there is just a lot we don’t know.”