Effect of inactivated influenza vaccination on human coronavirus infection: Secondary analysis of a randomized trial in Hutterite colonies. Issue 48 (26th November 2021)

• Record Type: Journal Article
• Authors: Chen, Andrew T.; Stacey, Hannah D.; Marzok, Art; Singh, Pardeep; Ang, Jann; Miller, Matthew S.; Loeb, Mark
• Is Part Of: Vaccine. Volume 39:Issue 48(2021)
• Page Start: 7058
• Page End: 7065
• Publication Date: 2021-11-26
• Subjects: Influenza -- Coronavirus -- Vaccine -- Clinical epidemiology -- Bystander activation; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2021.10.021
• Languages: English
• ISSNs: 0264-410X

Abstract

Abstract: Background: Although influenza vaccines provide protection against influenza viruses, concern has been raised that they may increase susceptibility to non-influenza respiratory viruses. As pandemic lockdowns end, temporal overlap of circulation of seasonal influenza viruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is expected. Understanding the impact of influenza vaccination on risk of coronavirus infection is therefore of considerable public health importance. Methods: We performed a secondary analysis of a randomized trial where children and adolescents in Canadian Hutterite colonies were randomly assigned by colony to receive the 2008–2009 seasonal inactivated trivalent influenza vaccine (TIV) or a control hepatitis A (HepA) vaccine. All 3273 colony members (vaccinated children and nonvaccine recipients) were followed for the primary outcome of RT-PCR confirmed seasonal coronavirus infection. Serum collected pre- and post-vaccination was analyzed for titers of IgG antibodies towards human coronaviruses (HCoV). Results: The incidence of coronavirus infection was 0·18/1000 person-days in the colonies that received TIV vs 0.36/1000 person-days in the control group, hazard ratio (HR) 0.49 [0.21–1.17]. The risk reduction among non-vaccine recipients in the TIV group compared to the control group was HR 0.55 [0.24–1.23]. There was an increase in the geometric mean fold change of HCoV-OC43 antibody titers following TIV compared to HepA vaccine (mean difference 1.2 [0.38–2.06], p = 0.007), and an increase in geometric mean HCoV-NL63 antibody titers post-TIV (262.9 vs 342.9, p = 0.03). Conclusion: The influenza vaccine does not increase the risk of a coronavirus infection. Instead, the influenza vaccine may reduce the rate of coronavirus infections by inducing cross-reactive anti-coronavirus IgG antibodies.