Decline of influenza and respiratory syncytial virus detection in facility-based surveillance during the COVID-19 pandemic, South Africa, January to October 2020

Abstract

Background In South Africa, COVID-19 control measures to prevent SARS-CoV-2 spread were initiated on 16 March 2020. Such measures may also impact the spread of other pathogens, including influenza virus and respiratory syncytial virus (RSV) with implications for future annual epidemics and expectations for the subsequent northern hemisphere winter. Methods We assessed the detection of influenza and RSV through facility-based syndromic surveillance of adults and children with mild or severe respiratory illness in South Africa from January to October 2020, and compared this with surveillance data from 2013 to 2019. Results Facility-based surveillance revealed a decline in influenza virus detection during the regular season compared with previous years. This was observed throughout the implementation of COVID-19 control measures. RSV detection decreased soon after the most stringent COVID-19 control measures commenced; however, an increase in RSV detection was observed after the typical season, following the re-opening of schools and the easing of measures. Conclusion COVID-19 non-pharmaceutical interventions led to reduced circulation of influenza and RSV in South Africa. This has limited the country’s ability to provide influenza virus strains for the selection of the annual influenza vaccine. Delayed increases in RSV case numbers may reflect the easing of COVID-19 control measures. An increase in influenza virus detection was not observed, suggesting that the measures may have impacted the two pathogens differently. The impact that lowered and/or delayed influenza and RSV circulation in 2020 will have on the intensity and severity of subsequent annual epidemics is unknown and warrants close monitoring.

The Influence of COVID-19 on Influenza and Respiratory Syncytial Virus Activities

“…Reports from other countries, including China, Australia, and France, also cited diminished flu cases since the pandemic was declared [ 26 , 27 ]. Stamm et al described a parallel decline in flu and RSV incidence in Germany in 2020, while Tempia et al reported a similar trend in South Africa [ 28 , 29 ]. Likewise, both flu and RSV cases declined in the USA in 2020.…”

Respiratory Syncytial Virus: New Challenges for Molecular Epidemiology Surveillance and Vaccination Strategy in Patients with ILI/SARI

“…Moreover, the use of an epidemiologic integrated approach has to be highlighted whereas the widest use of non-pharmaceutical interventions (NPIs) during the current COVID-19 pandemic has changed the epidemiologic scenario of influenza and other respiratory viruses [58,59], with a decline of influenza and hRSV detection followed by a resurgence of hRSV incidence in hospitalised children after the relaxation of public health measures [60,61]. Therefore, the importance of molecular epidemiology, in support of the surveillance systems in place against respiratory pathogens both in community and hospital settings, must be emphasised also in the light of a changing and more complex global public health scenario and of the increasing need to update vaccination strategies [62,63].…”

COVID-19 Lesson for Respiratory Syncytial Virus (RSV): Hygiene Works

“…In South Africa, a facility-based surveillance revealed a decline in RSV and influenza virus detection with strengthening of the most stringent COVID-19 control strategies, compared with previous years. However, a subsequent increase in RSV was observed after the typical season, possibly reflecting the easing of measures [58]. Indeed, further cost analysis studies would document a proportional drop in related medical costs in terms of billions of euros/dollars in those countries registering a drastic reduction in RSV hospitalization (up to 70-90%) during the containment measures following COVID-19.…”

“…In South Africa, a facility-based surveillance revealed a decline in RSV and influenza virus detection with strengthening of the most stringent COVID-19 control strategies, compared with previous years. However, a subsequent increase in RSV was observed after the typical season, possibly reflecting the easing of measures [ 58 ].…”