Flu season: Young children more likely to spread flu to others in their household

Young children had the most cases of symptomatic flu illness and were more likely to spread the flu to people in their household. Picture : Pexels / Polina Tankilevitch

Young children had the most cases of symptomatic flu illness and were more likely to spread the flu to people in their household. Picture : Pexels / Polina Tankilevitch

Published Apr 21, 2022

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Influenza, commonly known as flu, spreads quickly and can affect anyone, regardless of their state of health or their age.

Over 11 000 deaths related to flu occur in South Africa each year, and almost 50% of those in SA who catch severe flu, need hospitalisation.

Flu viruses circulate worldwide at different times of the year, and SA’s seasonal flu usually has the highest number of recorded cases between May and September.

A recent study in SA found that there was a high occurrence of flu in both rural and urban settings and also showed that people with no symptoms – particularly children – are able to transmit flu.5 In this study, around half of the people with flu had no symptoms – but they transmitted flu to 6% of their household contacts.

Young children had the most cases of symptomatic flu illness and were more likely to spread the flu to people in their household. Among children older than 5 years, 74% had flu symptoms, compared to 39% of adults aged 19-44 years.

Dr Thinus Marais, Medical Head: Africa Zone, Sanofi Pasteur, said: “Targeting vaccination towards children not only has the potential to reduce symptomatic disease in this at-risk group but also of reducing transmission in the community.”

He adds: “Flu vaccination is even more important now, given that simultaneous infection with flu and Covid-19 can result in severe disease. In the UK, a study from January to April 2020 showed that co-infection with flu and Covid-19 was associated with a two times higher risk of death and intensive care unit admission, compared with Covid-19 infection alone.”

“Flu vaccination is critical, considering the possible co-circulation of both the flu and Sars-Cov-2 viruses in the absence of a hard lockdown. It is important to remember that the flu vaccine will not prevent Covid-19 and vice versa; therefore, it is important to ensure that you are vaccinated against both,” says Marais.

According to the US Centres for Disease Control, during the 2019-2020 season, flu vaccination averted 7.5 million cases of flu, 3.7 million medical visits, 105 000 flu-associated hospitalisations, and 6 300 deaths.9

“It is important to note that due to non-pharmaceutical interventions such as mask-wearing and social distancing, the numbers of flu cases reported in 2020 and 2021 were reduced. The flu virus remains unpredictable, and experts expect a resurgence of cases as population movements and habits return to normal,” says Marais.

Guidance regarding having flu and Covid-19 vaccination at the same time is constantly being updated. At the time of publication, the Department of Health advises that while the flu vaccine can be given concurrently with other injectable, non-flu vaccines but must be administered at different injection sites, it should not be co-administered with Covid-19 vaccines.

As per the National Institute for Communicable Diseases (NICD), the Covid-19 vaccine should be administered with at least a 14-day interval between it and any other vaccine.

Recent studies have found that Covid-19 has caused people to have a higher risk of heart complications11 – which further expands the pool of high-risk people. Evidence has also shown that flu may predispose people to heart problems.

“In SA, annual flu recommendations encourage individuals at high risk of severe outcomes to get vaccinated. Remember that even healthy individuals who wish to protect themselves and those around them from getting the flu can consider vaccination annually,” says Marais.