A study recently published in the Journal of Medical
Virology showed that coinfection of SARS-CoV-2 and influenza virus was common during the initial COVID-19 outbreak in Wuhan , China , and patients who experienced coinfection had a higher risk of poor health outcomes .”
• immunomodulatory therapies for COVID-19 will affect the immune response to influenza vaccine . However , despite this uncertainty , as long as influenza viruses are circulating , an unvaccinated person with COVID-19 should receive the influenza vaccine once they have substantially improved or recovered from COVID-19 .”
Even with an understanding of each pathogen separately , scientists are still pondering the ramifications of the meshing of one seasonal pathogen with one that could potentially become endemic . The dynamics of co-infection are still not completely understood enough to successfully handle a potential concurrent COVID-19 and influenza outbreak .
The American Society for Microbiology ( 2020 ) acknowledges that co-infection was observed early in the outbreak : “… co-infection has been reported for SARS-CoV-2 and respiratory syncytial virus ( RSV ), rhinovirus , other Coronaviridae and the flu . A study recently published in the Journal of Medical Virology showed that coinfection of SARS-CoV-2 and influenza virus was common during the initial COVID-19 outbreak in Wuhan , China , and patients who experienced coinfection had a higher risk of poor health outcomes .”
“ We still have limited experience with co-infection with the two viruses ,” Talbot confirms . “ When the pandemic hit in the Northern hemisphere earlier this year , influenza was circulating and cases of co-infection were reported . As we moved to the quarantine and lockdowns , however , the incidence of influenza dropped dramatically . In the Southern hemisphere , the influenza season that occurred over the past few months ( during our summer ) showed very low influenza activity , attributed as well to the interventions in place to prevent spread of COVID-19 . It is clinically plausible that a person co-infected with both viruses could have a more severe presentation or outcome , but that is supposition at this point .”
The NIH ( 2020 ) points out that , “ Influenza activity in the United States during the 2020-2021 influenza season is difficult to predict and could vary geographically and by the extent of SARS-CoV-2 community mitigation measures . During early 2020 , sharp declines in influenza activity coincided with implementation of SARS-CoV-2 control measures in the United States and several Asian countries . Very low influenza virus circulation was observed in Australia , Chile , and South Africa during the typical Southern Hemisphere influenza season in 2020 . Clinicians should monitor local influenza and SARS-CoV-2 activity ( e . g ., by tracking local and state public health surveillance data and testing performed at healthcare facilities ) to inform evaluation and management of patients with acute respiratory illness .”
Balakrishnan ( 2020 ) observes that the low circulation of influenza virus “ could be matters of both reassurance and concern ,” adding that , “ The decreased circulation of the virus is likely largely attributable to the mandatory physical distancing and hygiene protocols implemented to curb the spread of SARS-CoV-2 . However , the potential impact of altered infection testing priorities , healthcare personnel capacity , and health seeking behaviors during the pandemic should not be ignored .”
The NIH ( 2020 ) advises that when influenza viruses and SARS-CoV-2 are co-circulating in the community , “ SARS-CoV-2 testing and influenza testing should be performed in all patients hospitalized with suspected COVID-19 or influenza . When influenza viruses and SARS-CoV-2 are cocirculating in the community , SARS-CoV-2 testing should be performed in outpatients with suspected COVID-19 , and influenza testing can be considered in outpatients with suspected influenza if the results will change clinical management of the illness . Several multiplex assays that detect SARS-CoV-2 and influenza A and B viruses have received Food and Drug Administration Emergency Use Authorization and can provide results in 15 minutes to 8 hours on a single respiratory specimen .” Clinicians are directed to consult the CDC ’ s resources on influenza virus testing as well as the recommendations of the Infectious Diseases Society of America ( IDSA ) on the use of influenza tests and interpretation of testing results .
Balakrishnan ( 2020 ) confirms the need to test : “ In addition to continuing adherence to non-pharmaceutical interventions ( NPIs ), one way to prepare for a possible double epidemic is to ramp up the testing capacity for both COVID-19 and seasonal infections … Combination testing for both COVID-19 and influenza could also be beneficial , as a single sample could be used to distinguish the two infections in patients presenting with similar symptoms … Another strategy to reduce the likelihood of a double epidemic would be to strengthen existing influenza vaccination programs . Healthcare workers are at the forefront of COVID-19 care and are likely to be mandated for influenza shots … However , expanding influenza shot programs does not come without difficulties . Several countries would have placed an order for the vaccine before the pandemic , so increasing the demand now could lead to a vaccine shortage . Moreover , realigned resources to vaccination programs during the pandemic might have a negative impact on the response to COVID-19 …. Overall , experts bet on the documented benefits of NPIs and believe that increased preparedness could prevent a serious double epidemic .”
As we have seen , there is evidence that COVID-19 measures may be mitigating the spread of seasonal influenza so far . Olsen , et al . ( 2020 ) report that , “ Following widespread adoption of community mitigation measures to reduce transmission of SARS-CoV-2 , the percentage of U . S . respiratory specimens submitted for influenza testing that tested positive decreased from more than 20 percent to 2.3 percent and has