Currently, there is no evidence linking influenza vaccination with poorer prognosis in patients with coronavirus disease 2019 (COVID-19). Therefore, a high coverage vaccination rate is needed for the upcoming 2020-2021 influenza season, according to a letter to the editor published in Clinical Infectious Diseases.
A potentially challenging situation for patients, clinicians, and public health systems worldwide could be on the horizon with a possible co-circulation of the influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the upcoming 2020-2021 influenza season. Although influenza and COVID-19 can cause similar clinical symptoms, including life-threatening pneumonia, correct diagnosis is essential for the proper management of patients; therefore, specific diagnostic procedures need to be implemented. The authors of this letter aimed to raise awareness about the lack of association between influenza vaccination and a higher risk for coronavirus-related severe outcomes.
The interaction of and co-existence between SARS-CoV-2 and the influenza virus in the same individual and what effect this interaction could have on mortality and other health outcomes remains uncertain. Public health systems may need to stretch their capacities in both primary care and hospital settings in terms of human resources, material, health policies, and costs.
Currently, the best-known and most effective public health intervention to prevent influenza outbreaks and avoid healthcare service overloads during a simultaneous COVID-19 pandemic is influenza vaccination. Worldwide, institutions including the World Health Organization (WHO) and the European Commission recommend seasonal influenza vaccination particularly for people within vulnerable populations, including the elderly, young children, pregnant women, healthcare professionals, and those with certain underlying chronic diseases.
Previous studies have also shown no evidence that influenza vaccination is associated with poorer prognosis in COVID-19 patients. A recent Canadian study that used data from 7 influenza seasons (2010-2017) reported that influenza vaccination was protective against influenza-like illness when the agent was an influenza virus; however, in cases of non-influenza viruses, including coronaviruses, influenza vaccination had neither a positive or negative effect and did not affect seasonal coronavirus risk. A recent Spanish PRECOVID study that was ongoing during the pandemic found that influenza vaccination was not associated with a higher likelihood of mortality in men or women (age-adjusted odds ratios, 1.24 and 1.23; 95% CI,zs 0.95-1.61 and 0.94-1.61, respectively).
The results of these studies suggest that efforts to mitigate preventable risks during the upcoming 2020-2021 influenza season should be made and a high vaccination coverage should be prioritized in vulnerable populations in an effort to establish herd immunity. “We strongly encourage healthcare professionals to follow the recommendations of the WHO regarding influenza vaccination,” the authors concluded.
González-Rubio F, Ioaeim-Skoufa I, Poblador-Plou B, Gimeno-Miguel A, Prados-Torres A. Influenza vaccination: an ally to mitigate influenza-associated risks during the coronavirus pandemics [published online August 11, 2020]. Clin Infect Dis. doi:10.1093/cid/ciaa1190/5891288