Breakthrough infections raise health, death risk; vaccine passports
without testing allow cases to be missed
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[November 22, 2021]
By Nancy Lapid
(Reuters) - The following is a summary of
some recent studies on COVID-19. They include research that warrants
further study to corroborate the findings and that has yet to be
certified by peer review.
Breakthrough COVID-19 raises risk of health problems, death
COVID-19 is generally less severe in vaccinated patients but that does
not mean breakthrough infections will be benign, a large study shows.
Researchers analyzed data collected by the U.S. Veterans Affairs
Administration from 16,035 survivors of breakthrough infections, 48,536
unvaccinated COVID-19 survivors and nearly 3.6 million uninfected
people. At six months after infection, after taking their risk factors
into account, people with breakthrough infections had lower rates of
death and long-term lingering health problems than COVID-19 patients who
had not been vaccinated. But compared to people who never had COVID-19,
those who had breakthrough infections had a 53% higher risk of death and
a 59% higher risk of having at least one new medical condition,
particularly problems affecting the lungs and other organs. Even when
breakthrough infections did not require hospitalization, the increased
risks of death and lasting effects were "not trivial," the research team
reported on Monday on Research Square ahead of peer review. "The overall
burden of death and disease following breakthrough COVID-19 will likely
be substantial," the researchers conclude.
Vaccine passports would allow infections to be missed
"Vaccine passports" that exempt vaccinated people from regular COVID-19
testing would allow many infections to be missed, Israeli data suggest.
Researchers analyzed infection rates in citizens returning to Israel
through Ben-Gurion airport, for whom PCR tests upon arrival are required
regardless of vaccination status. "Surprisingly," in August 2021, the
rate of positive tests among vaccinated travelers was more than double
the rate among the unvaccinated, said Retsef Levi of the MIT Sloan
School of Management, coauthor of a report posted on the SSRN server
ahead of peer review. Travelers who had received the second dose of the
Pfizer/BioNTech vaccine within the past six months or who had received a
booster dose were considered vaccinated. The group considered to be
unvaccinated included the never-vaccinated and those whose most recent
shot was more than six months prior, given evidence of waning vaccine
efficacy by then. In September, when the Israeli government was
recommending booster shots for all adults, the positive-test rate
dropped among vaccinated travelers and was about 3.5 times lower with
vaccination than without.
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A health worker takes a dose of the coronavirus disease (COVID-19)
vaccine from a vial during the roll out of mass vaccination in
Abuja, Nigeria, November 19, 2021. REUTERS/Afolabi Sotunde
By October, the positive-test rate in the
vaccinated group, while still lower, had started to climb again, Levi
said. The data suggest that limiting frequent COVID-19 testing to
unvaccinated people would "pose potential risks by reinforcing the
misrepresentation that vaccinated individuals are protected from
infections."
Masks, social distancing still worthwhile
Mask wearing and physical distancing are tied to reductions in the
spread of COVID-19 and should be continued, according to researchers
who reviewed 72 previous studies. When they analyzed results from
eight of the studies in detail, they saw a 53% reduction in the
incidence of COVID-19 with mask wearing and a 25% reduction with
physical distancing. There is not yet enough data to confirm the
overall benefits of more stringent measures such as lockdowns,
school and workplace closures, and border closures, the researchers
reported on Thursday in The BMJ. Very few of the studies analyzed
were randomized trials, so they cannot prove the interventions
directly reduced infection rates. Still, the researchers conclude,
"It is likely that further control of the COVID-19 pandemic depends
not only on high vaccination coverage and its effectiveness but also
on ongoing adherence to effective and sustainable public health
measures."
(Reporting by Nancy Lapid; Editing by Bill Berkrot)
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