Easing of Covid-19 travel restrictions in S'pore could lead to uptick in flu cases, doctors warn

More people will be travelling abroad during the northern winter that typically sees countries there experiencing a spike in flu cases. PHOTO: ST FILE

SINGAPORE - People should take their flu jabs to protect against concurrent infection of both Covid-19 and the flu, which can lead to severe disease, doctors have advised.

This is especially important as Singapore continues to ease its travel restrictions and opens up its borders, they said, adding that influenza cases can be expected to rise.

With the new vaccinated travel lanes, more people here will be travelling abroad during the northern winter that typically sees countries there experiencing a spike in flu cases.

In Singapore, Covid-19 safe management measures such as social distancing and mask wearing have been known to keep in check other unrelated respiratory virus infections, including influenza and the common cold.

This was proven in a research study conducted by doctors from the Singapore General Hospital (SGH), KK Women's and Children's Hospital (KKH) and the Genome Institute of Singapore.

The study, published in the scientific journal Jama Network on June 28, combined data from more than 42,000 polymerase chain reaction tests for respiratory viruses across three public hospitals in 2019 and 2020.

Dr Wan Wei Yee, the first author of the study, warned that Singapore travellers will find some countries like the United States and those in Europe having less stringent Covid-19 safe management measures - such as mask wearing and safe distancing not being mandated.

This could mean greater exposure to the flu, and bringing the virus back could put the elderly and more vulnerable people at risk of severe illness or even death, said Dr Wan, a senior consultant at the Department of Microbiology at SGH.

These risks could be mitigated if more people also get vaccinated for flu on top of the Covid-19 vaccines.

Dr Matthias G. Maiwald, a corresponding author of the study, noted a decline in the number of respiratory virus cases from February to March last year and during the circuit breaker period from April to June last year. Singapore raised the Dorscon alert level to orange in February 2020.

This could be attributed to the pandemic response measures - travel restrictions, social distancing, mask wearing and school closures - which likely contributed to bringing down the number of respiratory virus infections, added Dr Maiwald, head and senior consultant in the Microbiology Service of the Department of Pathology and Laboratory Medicine at KKH.

In comparison, Singapore saw a higher number of flu cases in December 2019 and January 2020, which typically coincides with year-end spikes as people usually travel overseas, said Dr Maiwald.

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He noted that Singapore typically has two flu seasons - from December to February and from May to July, which coincide with the winter season in the northern and southern hemispheres respectively.

Dr Esther Tan, a consultant at the Department of Respiratory and Critical Care Medicine at SGH, who was not involved in the study, said that based on studies done in the United States and China, about 3 per cent to 10 per cent of Covid-19 patients also developed other viral infections, with the most common being influenza.

She added that getting a co-infection could be worrying for patients who have other long-term illnesses as this would mean increased chances of hospitalisation or death.

Dr Tan recommended getting a flu jab before the incoming flu season at the end of the year. The flu jab should be taken 14 days before or after the Covid-19 vaccine.

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