Influenza and COVID-19 co-infection and vaccine effectiveness against severe cases: a mathematical modeling study

Front Cell Infect Microbiol. 2024 Mar 4:14:1347710. doi: 10.3389/fcimb.2024.1347710. eCollection 2024.

Abstract

Background: Influenza A virus have a distinctive ability to exacerbate SARS-CoV-2 infection proven by in vitro studies. Furthermore, clinical evidence suggests that co-infection with COVID-19 and influenza not only increases mortality but also prolongs the hospitalization of patients. COVID-19 is in a small-scale recurrent epidemic, increasing the likelihood of co-epidemic with seasonal influenza. The impact of co-infection with influenza virus and SARS-CoV-2 on the population remains unstudied.

Method: Here, we developed an age-specific compartmental model to simulate the co-circulation of COVID-19 and influenza and estimate the number of co-infected patients under different scenarios of prevalent virus type and vaccine coverage. To decrease the risk of the population developing severity, we investigated the minimum coverage required for the COVID-19 vaccine in conjunction with the influenza vaccine, particularly during co-epidemic seasons.

Result: Compared to the single epidemic, the transmission of the SARS-CoV-2 exhibits a lower trend and a delayed peak when co-epidemic with influenza. Number of co-infection cases is higher when SARS-CoV-2 co-epidemic with Influenza A virus than that with Influenza B virus. The number of co-infected cases increases as SARS-CoV-2 becomes more transmissible. As the proportion of individuals vaccinated with the COVID-19 vaccine and influenza vaccines increases, the peak number of co-infected severe illnesses and the number of severe illness cases decreases and the peak time is delayed, especially for those >60 years old.

Conclusion: To minimize the number of severe illnesses arising from co-infection of influenza and COVID-19, in conjunction vaccinations in the population are important, especially priority for the elderly.

Keywords: SARS-CoV-2; co-infection; compartmental model; influenza; vaccination.

MeSH terms

  • Aged
  • COVID-19 Vaccines
  • COVID-19* / epidemiology
  • COVID-19* / prevention & control
  • Coinfection* / epidemiology
  • Humans
  • Influenza A virus*
  • Influenza Vaccines*
  • Influenza, Human* / epidemiology
  • Influenza, Human* / prevention & control
  • Middle Aged
  • SARS-CoV-2
  • Vaccination
  • Vaccine Efficacy

Substances

  • Influenza Vaccines
  • COVID-19 Vaccines

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the National Basic Research Priorities Program of China (Grant No. 2023YFC3041600), the National Key Research and Development Program of China (No. 2022YFC2600705); Self-supporting Program of Guangzhou Laboratory (Grant No. SRPG22-007); Science and Technology Development Fund of Macau SAR (005/2022/ALC); Science and Technology Program of Guangzhou (No. 2022B01W0003); Science and Technology Program of Guangzhou (Grant No. 202102100003); Science and Technology Development Fund of Macau SAR(0045/2021/A); Macau University of Science and Technology (FRG-20-021-MISE); and National Natural Science Foundation of China (Grant No. 82361168672).