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

• Published in: Frontiers in cellular and infection microbiology 2024-03, Vol.14, p.1347710-1347710
• Main Authors: Liang, Jingyi, Wang, Yangqianxi, Lin, Zhijie, He, Wei, Sun, Jiaxi, Li, Qianyin, Zhang, Mingyi, Chang, Zichen, Guo, Yinqiu, Zeng, Wenting, Liu, Tie, Zeng, Zhiqi, Yang, Zifeng, Hon, Chitin
• Format: Article
• Language: English
• Subjects: Aged; Cellular and Infection Microbiology; co-infection; Coinfection - epidemiology; compartmental model; COVID-19 - epidemiology; COVID-19 - prevention & control; COVID-19 Vaccines; Humans; influenza; Influenza A virus; Influenza Vaccines; Influenza, Human - epidemiology; Influenza, Human - prevention & control; Middle Aged; SARS-CoV-2; Vaccination; Vaccine Efficacy
• ISSN: 2235-2988; 2235-2988
• DOI: 10.3389/fcimb.2024.1347710

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. 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. 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. 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.