New study finds that South Africa has high influenza burden

• Asymptomatic people drive flu infections
• Children under the age of five years have the highest rates of flu
• Researchers say that vaccinating children is the key to lowering flu transmission rates

A new South African study has found that people with asymptomatic flu infections are a significant driver of transmitting flu viruses. 

The research published in The Lancet Global Health suggests that strategies, such as quarantine and isolation, might be ineffective to control influenza, and vaccines may be the most effective way to slow down transmission.

Collecting samples

The study conducted by the National Institute for Communicable Diseases (NICD), Perinatal HIV Research Unit, WITS Agincourt HDSS and the US Centres for Disease Control and Prevention collected  81 430 nasopharyngeal samples from 1 116 participants in 225 households in the North West and Mpumalanga.

Nasopharyngeal samples were collected twice a week and tested in labs for influenza between 2017 and 2018. Households with two or more people living together were included in the study.

Tracing transmissions

The findings of the study show that young children were more likely to transmit influenza. Children under five years of age had the highest rates of flu infection and repeat infections. With increasing age, the rates of infection, however, decreased.

The research also found that more than 35% of the people had at least one infection annually, and 17% of them had a repeat infection during the same year.

The results also show that just more than half of the flu infections were symptomatic, indicating the presence of a high number of asymptomatic influenza infections. Asymptomatic people accounted for transmitting the flu to approximately 6% of household contacts.

According to the study authors, this indicates that strategies, such as quarantine and isolation, might not be effective to control influenza and that the key to lowering flu transmission is the vaccination of children.

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