Influenza, which is also referred to as flu, is caused by influenza viruses that affect the nose, throat and sometimes the lungs.

The US Centers for Disease Prevention and Control’s (CDC) recent Morbidity and Mortality Weekly Report (MMWR) states that influenza activity in the US and the rest of the world has come down in the midst of the pandemic. As a result of the mitigation measures adopted to control the spread of the SARS-CoV-2 virus, the percentage of respiratory symptoms submitted for influenza testing in the US has come down to 2.3 per cent, as compared to just under 20 per cent otherwise.

What is influenza?

Influenza, which is also referred to as flu, is caused by influenza viruses that affect the nose, throat and sometimes the lungs. Influenza can cause mild to severe illness and, in some cases, death. The best way to prevent influenza is by getting vaccinated each year. Flu viruses are spread through tiny droplets that are released when infected people cough, sneeze or talk.

Some of the symptoms of the flu and COVID-19 are similar, these include fever, cough, shortness of breath, fatigue, sore throat, stuffy nose and muscle pain among others.

According to a 2018 study published in Clinical Infectious Diseases (CID), the incidence of influenza among all age groups in the US is 3-11.3 per cent. Between October 2019 and April 2020, the CDC’s preliminary estimates suggest that over 39 million to 56 million were infected with flu, between 410,000 and 740,000 were hospitalised and roughly 24,000-62,000 died.

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What is the reason for low influenza activity during the pandemic?

There could be a few reasons, one being the interventions aimed at controlling the transmission of SARS-CoV-2 and the administration of influenza vaccination that could have reduced the incidence of influenza in the 2020-2021 northern hemisphere season. Initially, the decline in influenza virus activity was attributed to decreased testing since due to the pandemic people who presented with respiratory symptoms were typically examined for COVID-19 first. However, subsequent efforts by public health officials to find cases of influenza revealed little to no detection of influenza virus.

In the months of June-August 2020, which are considered typical influenza season for the Southern Hemisphere, countries such as Australia, Chile and South Africa reported low levels of influenza activity. The report notes that the incidence of influenza has been at “historically low” levels.

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