The following is a summary of some of the most recent studies on COVID-19. They include studies that require further research to confirm results and have not yet been certified by peer review.
Breakthrough COVID-19 increases the risk of health problems and death
A large study suggests that COVID-19 is usually less severe in vaccinated patients, but this does not mean that breakthrough infections are benign. Researchers analyzed data collected by the U.S. Veterans Affairs Administration from 16,035 survivors of breakthrough infection, 48,536 unvaccinated COVID-19 survivors and nearly 3.6 million uninfected people. Six months post-infection, after accounting for their risk factors, people with breakthrough infection had lower mortality rates and long-term lingering health problems compared to unvaccinated COVID-19 patients. But those who developed breakthrough infections had a 53 percent higher risk of death and a 59 percent higher risk of at least one new disease, particularly problems affecting the lungs and other organs, compared with those who had never been infected with COVID-19. The peer review took place Monday at Research Place. The researchers concluded, "The overall burden of death and disease after breakthrough COVID-19 can be substantial."
Vaccine Passport Would Allow Missed Infections
Israeli data suggest that a "vaccine passport" that exempts vaccinated people from routine COVID-19 testing would allow many infections to be missed. Researchers analyzed infection rates among citizens returning to Israel through Ben Gurion Airport, who were required to undergo PCR testing upon arrival regardless of vaccination status. "Surprisingly," in August 2021, the rate of positive tests among vaccinated travelers was more than twice that of unvaccinated people, said Retsef Levi of the MIT Sloan School of Management, who co-authored a report published on the SSRN server prior to peer review... Travelers who received a second dose of Pfizer (PFE.N)/BioNTech vaccine within the past six months or who had received a booster dose were considered vaccinated. The group considered unvaccinated included those who had never been vaccinated and those whose most recent dose was more than six months old, as the vaccine was losing effectiveness by that time. in September, when the Israeli government recommended a booster dose for all adults, the positive test rate for vaccinated travelers declined, and the positive test rate for vaccinated travelers was approximately 3.5 times lower than that for unvaccinated ones. By October, the positive test rate for the vaccinated group, while still low, had begun to climb again, Levi said. The data suggest that limiting frequent COVID-19 testing to unvaccinated individuals would "pose a potential risk by reinforcing the misrepresentation that vaccinated individuals are safe from infection.
Wearing a mask and maintaining social distance is still worthwhile
Researchers reviewed 72 previous studies and said that wearing masks and maintaining physical distance is associated with reduced transmission of COVID-19 and should be continued. When they analyzed the results of eight studies in detail, they found that wearing a mask reduced the incidence of COVID-19 by 53 percent, while maintaining physical distance reduced it by 25 percent. There is not enough data to confirm the overall benefits of stricter measures, such as lockdowns, school and workplace closures, and border closures, the researchers reported Thursday in the BMJ... Few of the studies analyzed had randomized trials, so they could not demonstrate that the interventions directly reduced infection rates. Nevertheless, the researchers conclude that "further control of the COVID-19 pandemic is likely to depend not only on high vaccination coverage and its effectiveness, but also on continued adherence to effective and sustainable public health measures."