European Journal of Cardiovascular Medicine

Influenza virus infection in humans is a zoonotic disease having high economic and public health impacts. Outbreaks of overlapping respiratory viral infections have been reported in the past. Here we describe the characteristics of a similar viral outbreak that occurred among students in a University campus in Kerala, India, during May, 2022. We conducted an epidemiologic investigation to describe the outbreak and elucidate the dynamics of viral transmission.  Nasal swabs were collected randomly from suspected patients. Real-time reverse transcription polymerase chain reaction (RT-PCR)-based diagnosis was performed to detect influenza A and B viruses followed by sequencing and phylogenetic analysis. COVID 19 was tested using rapid antigen detection kits. Of the 185 affected students included in the outbreak investigation, 87% reported either respiratory or gastrointestinal symptoms or both. The median time taken for the onset of symptoms was 3 days. Out of 16, 11 sampleswere laboratory confirmed for Influenza A (H3N2) while 18 samples were positive for COVID 19. The phylogenetic analysis showed that the Influenza virus is close to the current, Darwin 2021 vaccine strain. The only stool sample collected, turned positive for Noro Virus. Risk factors for infection included close proximity and exposure to droplet infection. The public health response included isolation of cases, contact tracing, temporary shutdown of college and hostels and enforcement of COVID appropriate behaviour in the campus. Early laboratory confirmation and an immediate public health response contained the outbreak.