An observational study of Italian healthcare employees contaminated with SARS-CoV-2 who did not require hospitalization suggests a hyperlink between two or three doses of vaccine and a decrease prevalence of lengthy COVID.
Within the modeling research, revealed late final week in JAMA, researchers in Milan studied 2,560 employees at 9 healthcare services from March 2020 to April 2022. All healthcare employees had been mandated to obtain three doses of the Pfizer/BioNTech mRNA COVID-19 vaccine in 2021. And all had been screened for COVID-19 as soon as per week or each 2 weeks and after they developed signs or had been uncovered to the virus.
Contributors accomplished a survey from February to April 2022 about their demographic elements, underlying situations, and COVID-19–associated signs throughout and after their an infection. Lengthy COVID was outlined because the presence of not less than one symptom for greater than 4 weeks.
Odds of lengthy COVID fell to 16% after third dose
Of the two,560 employees, 739 (29%) examined optimistic for COVID-19, 89 of whom had no signs and 229 (31%) of whom had lengthy COVID.
Lengthy COVID prevalence modified over the course of the pandemic, from 48.1% within the first wave (February to September 2020) with the wild-type virus, to 35.9% within the second surge (October 2020 to July 2021) amid the Alpha variant, and 16.5% within the third wave (August 2021 to March 2022) with Delta and Omicron.
The variety of vaccine doses was linked to decrease prevalence of lengthy COVID, at 41.8% of a reference group of unvaccinated contributors, 30.0% after one dose, 17.4% after two doses, and 16.0% after the third dose. Threat elements for lengthy COVID included older age, excessive physique mass index, allergic reactions, and obstructive lung illness.
In contrast with a reference group of unvaccinated girls with no allergic reactions or underlying ailments within the first wave, a decrease chance of lengthy COVID within the research group was tied to male intercourse (odds ratio [OR], 0.65), two vaccine doses (OR, 0.25), and three vaccine doses (OR, 0.16). Threat elements for lengthy COVID included older age (OR, 1.23), allergic reactions (OR, 1.50), and extra underlying sicknesses (OR, 1.32).
There have been no vital associations between lengthy COVID and an infection wave or time between the second vaccine dose and an infection (OR, 0.66).
“On this longitudinal observational research performed amongst well being care employees with SARS-CoV-2 infections not requiring hospitalization, 2 or 3 doses of vaccine, in contrast with no vaccination, had been related to decrease lengthy COVID prevalence,” the research authors wrote. “Research limitations embody that signs and length had been self-reported, and causality can’t be inferred.”