Flu vaccine associated with lower COVID likelihood, hospitalizations
People who received their flu vaccine were less likely to test positive for COVID-19, and if they were infected with the virus, they were less likely to need hospitalization, mechanical ventilation, or a longer hospital stay, according to a study published today in the American Journal of Infection Control.
The researchers created a retrospective cohort of 27,201 patients who were tested for COVID-19 from Feb 27 to Jul 15, 2020, in the Michigan Medicine healthcare system. Of those, they found that 12,997 (47.8%) were vaccinated against the flu between Aug 1, 2019, to Jul 15, 2020. Of that number, 525 (4.0%) tested positive for coronavirus. Of the 14,204 (52.%) not vaccinated, 693 (4.9%) got COVID-19.
Using adjusted multivariable logistic regression analysis, the researchers found that those who received the flu vaccine had a 0.76 odds ratio (OR) of getting infected with COVID-19 (95% confidence interval [CI], 0.68 to 0.86; P < 0.001).
The flu-vaccinated group also had lower likelihood of COVID-19–related hospitalizations (OR, 0.58; 95% CI, 0.46 to 0.73; P < 0.001), mechanical ventilation (OR, 0.45; 95% CI, 0.27 to 0.78; P = 0.004), and long hospital stay (approximately 12 vs 16 average days, vaccinated vs unvaccinated; risk ratio, 0.76; 95% CI, 0.65 to 0.89, P < 0.001). No significant differences were found when looking at adjusted odds for intensive care or mortality.
The researchers suggest that the better COVID outcomes in the flu-vaccinated group could be due to the vaccine’s possible heterologous immune effects, but more research is needed to understand behavioral and sociodemographic differences in those who get the flu vaccine.
Still, they conclude, “Until the COVID-19 vaccine becomes widely available, the influenza vaccine should be promoted to reduce the burden of disease during this pandemic.”
Feb 22 Am J Infect Control study
Persistent COVID-19 symptoms detailed months after recovery
One third of symptomatic COVID-19 patients continued to experience symptoms about 5.6 months after their infection began, according to a research letter published late last week in JAMA Network Open. The researchers noted that their study was purely descriptive because of the small participant number.
University of Washington researchers received 117 surveys from COVID-19 patients between August and November 2020. Of these, 11 (6.2%) were asymptomatic, 150 (84.7%) were outpatients with mild symptoms, and 16 (9.0%) needed hospitalization.
The most common symptom reported was fatigue or loss of smell or taste (both were 13.6% of symptomatic participants), but 13.0% reported other symptoms such as brain fog (2.3%). Overall, 32.7% of outpatients and 31.3% of hospitalized patients reported at least one lingering symptom.
More than a third (35.3%) of people who had high blood pressure or diabetes experienced at least one ongoing symptom. Quality of life decreased for 30.7% of outpatients and hospitalized patients, and 7.9% reported that their COVID-19 symptom(s) negatively affected at least one daily living activity, most commonly household chores.
Survey responses came in a median of 169 days (range, 31 to 300) after illness onset in the COVID-19 group. Continuing symptoms occurred across all age ranges, with the least reported in participants 18 to 39 (26.6%) and the most in those 65 and older (43.3%).
A 21-person, healthy control group also took the survey a median of 87 days after enrollment, and 4.8% reported at least 1 persistent COVID symptom.
“To our knowledge, this study presents the longest follow-up symptom assessment after COVID-19 infection,” the researchers write. “Our research indicates that the health consequences of COVID-19 extend far beyond acute infection, even among those who experience mild illness.”
Feb 19 JAMA Netw Open research letter