An influenza A (H3N2) virus outbreak in the Kingdom of Cambodia during the COVID-19 pandemic of 2020

Abstract

Background: Global influenza virus circulation decreased during the COVID-19 pandemic, possibly due to widespread community mitigation measures. Cambodia eased some COVID-19 mitigation measures in June and July 2020. On 20 August a cluster of respiratory illnesses occurred among residents of a pagoda, including people who tested positive for influenza A but none who were positive for SARS-CoV-2. Methods: A response team was deployed on 25 August 2020. People with influenza-like illness (ILI) were asked questions regarding demographics, illness, personal prevention measures, and residential arrangements. Respiratory swabs were tested for influenza and SARS-Cov-2 by real-time reverse transcription PCR, and viruses were sequenced. Sentinel surveillance data were analyzed to assess recent trends in influenza circulation in the community. Results: Influenza A (H3N2) viruses were identified during sentinel surveillance in Cambodia in July 2020 prior to the reported pagoda outbreak. Among the 362 pagoda residents, 73 (20.2%) ILI cases were identified and 40 were tested, where 33/40 (82.5%) confirmed positive for influenza A (H3N2). All 40 were negative for SARS-CoV-2. Among the 73 residents with ILI, none were vaccinated against influenza, 47 (64%) clustered in 3/8 sleeping quarters, 20 (27%) reported often wearing a mask, 27 (36%) reported often washing hands, and 11 (15%) reported practicing social distancing. All viruses clustered within clade 3c2. A1 close to strains circulating in Australia in 2020. Conclusions: Circulation of influenza viruses began in the community following the relaxation of national COVID-19 mitigation measures, and prior to the outbreak in a pagoda with limited social distancing. Continued surveillance and influenza vaccination are required to limit the impact of influenza globally.

Bioassay-Guided Fractionation of Siparuna glycycarpa n-Butanol Extract with Inhibitory Activity against Influenza A(H1N1)pdm09 Virus by Centrifugal Partition Chromatography (CPC)

“…In July 2020, during the worldwide pandemic of COVID-19, an outbreak of another influenza A subtype, A(H3N2), occurred in the Kingdom of Cambodia. Among the Pagoda residents, 82.5% tested positive for this virus [3]. Therefore, the search for anti-influenza compounds that may prevent and treat serious infections and reduce transmissibility is pivotal.…”

Genetic and Antigenic Characterization of an Influenza A(H3N2) Outbreak in Cambodia and the Greater Mekong Subregion during the COVID-19 Pandemic, 2020

“…Influenza activity, for example, has remained at historically low levels globally since March 2020, even when increased influenza testing was performed in some countries ( 11 , 12 ). Interestingly, the majority of influenza detections in 2020 and in the first part of 2021 have been in Southeast Asia and other tropical regions such as Western Africa ( 13 – 15 ).…”

“…Due to a robust and swift response, SARS–CoV-2 was well managed and controlled in Cambodia and other parts of the GMS, and Cambodia detected no widespread community transmission throughout 2020. However, in July 2020, influenza detections began to increase in the Cambodian influenza-like illness (ILI) sentinel surveillance systems reflecting a country-wide outbreak that included clustered cases in closed/semi-closed settings (prisons/pagodas) and spreading into the general community ( 13 ). Influenza cases were subsequently detected in Vietnam, Laos PDR, and Thailand ( 14 , 15 ) by their WHO National Influenza Centers (NICs).…”

Influenza season 2020–2021 did not begin in Finland despite the looser social restrictions during the second wave of COVID‐19: A nationwide register study

“…8,9 Furthermore, influenza epidemic outbreaks were reported as the restrictions were eased. 10 In Australia, there was a significant increase in cases of respiratory syncytial viruses as the restrictions were lifted. 11 The goal in Finland was to keep schools open and restrict the spread of COVID-19 by implementing the test, track, and used less personal protection and did not change behavior.…”