As predictions of a difficult winter pour in, projecting rapid increases in COVID-19 infections, the World Health Organisation (WHO) has urged countries in the northern hemisphere to test for influenza alongside coronavirus.

WHO reassrerted today that surveillance systems are in place to help identify which influenza viruses are circulating, and suggested that countries be proactive in testing for the virus during the COVID-19 pandemic to prevent overwhelming healthcare systems with late or misdiagnoses.

The warning comes as the United States and countries across Europe reached record numbers of cases detected.

“There is also substantial work underway to ensure that patients enter the correct clinical care pathway as they enter the public health system,” stated Dr Maria Van Kerkhove, COVID-19 Technical Lead at the WHO, asserting that entering the clinical care pathway earlier will save lives. Some of these steps include detecting cases that may have been imported from overseas, identifying case clusters and investigating outbreaks.

Restrictions that have been implemented to restrict the spread of SARS-CoV-2 will also be beneficial in curbing the spread of influenza, but diagnosis of these illnesses could present a significant challenge as both viruses share similar symptoms. Because of this, testing and identifying which virus a patient has will be vital in making sure they receive appropriate care.

“We don’t yet know how the influenza season will unfold,” said Dr Van Kerkhove, COVID-19 Technical Lead at the WHO, speaking at a media briefing. Referring to a vaccine rollout, she added: “The good news is that we are prepared for this.”

‘Virtually no Influenza Circulation’ During Southern Hemisphere’s Winter

WHO’s warning for countries continuing to test for influenza comes despite the southern hemisphere’s relatively low number of cases seen during its winter, which recently concluded.

When the pandemic began in March, the southern hemisphere was entering its flu season. But flu cases dropped significantly compared to previous years, with the US Centers for Disease Control and Prevention stating there was “virtually no influenza circulation” in the southern hemisphere.

According to WHO, which tracks influenza activity around the globe, only 0.1% of people who were tested for flu in the southern hemisphere proved positive. This is contrasted to a typical rate of 5 in 10. The cause behind the sharp drop was attributed to COVID-19 restrictions and guidance like social distancing and hand washing.

Children and Pregnant Women at More Severe Risk from Influenza

While some at-risk categories for the two viruses do overlap, there are unique groups at risk for each. One of the most notable examples is young children. COVID-19 poses very little risk among younger children, however they are at increased risk for severe disease with influenza. Pregnant women are also at risk of severe disease with influenza but are not with COVID-19 – even two weeks after delivery.

“If [you know] someone with an acute respiratory infection and they are a young child or they are pregnant, that patient does need to be tested,” said Dr Janet Diaz, Head of Clinical Care at the WHO.

Current recommendations indicate that healthcare workers and people over 65, who are at double risk, need to be prioritised for vaccination. Pregnant women and children under 5 are to be offered vaccinations as supplies allow. WHO is due to publish further guidance on influenza soon.

Dr Diaz also noted that while corticosteroids are currently being used for treating patients with severe and critical COVID-19, as it reduces mortality, those drugs may not be suitable for influenza. With flu, there is concern that corticosteroids can increase viral replication.

She warned that governments must “understand when influenza starts to circulate in the community” in order to remain on top of cases.

Image Credits: Flickr: Joseph Gage.