Masks come down, respiratory infections go up for young kids

Specialist Leong Hoe Nam said, “All three years of [Covid-19] infection are squeezed into a six- to 12-month session.”

Judith Tan

Judith Tan

The Straits Times


Noah Fatrish, three, was warded on April 10. He was diagnosed with Influenza A and pneumonia. PHOTOS: COURTESY OF IZYAN SHUBLI

April 17, 2023

SINGAPORE – Noah Fatrish and Luth were born during the Covid-19 pandemic, when lockdowns, mask wearing and social distancing were the norm.

Both boys, who are three years old in 2023, were kept safe and far from the madding crowd from birth.

Since many Singaporeans no longer wear masks and behave more like they did pre-pandemic, both boys have been introduced to life at childcare centres – and have fallen sick frequently. Their mothers find themselves making regular trips to clinics and hospitals.

Luth’s mother, Ms Nabilah Awang, 30, said: “It felt like I had dipped my son into a cesspool of childhood germs. Luth came back with Covid-19, HFMD (hand, foot and mouth disease) and flu – the illnesses were a monthly occurrence. Last November, he was in intensive care at National University Hospital (NUH) with both Influenza A and RSV (respiratory syncytial virus).”

Ms Nabilah, who works in commodities, “freaked out then because of the death of a boy who was infected with Covid-19, Influenza A and RSV, and Luth had two of the three viruses”. She was referring to Zaheer Raees Ali, aged 1½, who died in June 2022 after being infected with Covid-19 and two other viruses.

Dr Li Jiahui, head of the Infectious Disease Service of the Department of Paediatrics at KK Women’s and Children’s Hospital (KKH), said it is not uncommon to catch infections by respiratory viruses “now and then”.

“The easing of safe management measures has contributed to an increase in the number of infections caused by respiratory viruses. Children in 2020 and 2021 had less exposure to common respiratory viruses compared with those of similar age in the previous years, due to enhanced hygiene practices during the Covid-19 pandemic. The lack of exposure has contributed to a rise in the number of children experiencing respiratory tract infections caused by common respiratory viruses,” Dr Li said.

Agreeing, Dr Rie Aoyama from the Division of Paediatric Infectious Diseases at the Khoo Teck Puat – National University Children’s Medical Institute at NUH said that while the lockdown, social distancing and mask wearing did not necessarily “affect, compromise or make significant changes to our immune systems, it does result in an immunity debt”.

“There was reduced exposure to viruses such as influenza, respiratory syncytial virus and rhinovirus, when children were younger. They are currently ‘catching up’ on the exposure to all the circulating viruses that they were not exposed to,” she said.

Infectious diseases specialist Leong Hoe Nam said: “Without the Covid-19 years, we would have had our regular infections for two to three years running. But when masks came down, the infections went up. All three years of infection are squeezed into a six- to 12-month session.”

“Children who were born just before and during Covid-19 were not exposed to minimal infections and now, they are exposed to all at the same time. We had our revenge travel. The viruses now have their revenge infection,” he said, adding that children seem sicker because they have not “earned their stripes” by going through different infections during the pandemic and immediately after.

It is this revenge infection that has put Noah Fatrish in the throes of a viral attack. He was hospitalised last Monday after his fever, which started on April 5, got worse.

His mother Izyan Shubli, 29, an infantcare teacher, said: “We had noticed he was slightly off his game when he came back from childcare and had a fever of 38 deg C. Since he had a history of bronchitis, we didn’t want to gamble with his health. At the clinic, he tested negative for Covid-19 and was diagnosed with a viral fever. When his chesty cough got worse after the Good Friday weekend, we immediately took him to hospital.”

Noah was diagnosed with Influenza A at KKH and because he had developed pneumonia, he was hospitalised and treated with antibiotics and Tamiflu. He will remain at the hospital until his pneumonia goes away, his mother said.

RSV is a common respiratory virus that usually causes mild, cold-like symptoms and most people recover in a week or two, but it can be serious in infants and the elderly, resulting in bronchiolitis and pneumonia. There is presently no RSV vaccine proven to reduce infection, but there are quite a few being developed.

The current caseload of influenza, RSV and even Covid-19 infections, among both adults and children, has increased and cases of respiratory infections seem to have ticked upwards after “masks down” announcements were made – first in August 2022, and again in February 2023.

According to the Ministry of Health (MOH) website, average daily consultations at polyclinics showed an increase of between 2.8 per cent and 22.7 per cent week on week in cases of acute upper respiratory infections after both announcements. Also, general practitioners estimated a 20 per cent to 30 per cent increase in the number of patients with flu-like symptoms since late December 2022.

But Professor Paul Tambyah, a senior consultant at the Division of Infectious Diseases at NUH, said there is no evidence to suggest that the innate immune response “has been blunted by any of the measures used against Covid-19”.

“The reality is that most of us have been exposed to a range of viruses since childhood, and thus develop an adaptive response which protects us from severe infection later on in life, but not always, as there are different strains of these viruses circulating, depending on geography,” he said.

Dr Wan Wei Yee, a senior consultant at the Department of Microbiology at Singapore General Hospital, said that to get a true perspective on an actual “rise” in the cases of upper respiratory tract infection (URTI), “the number of reported cases in the week when the restrictions were lifted needs to be compared with the same week in pre-Covid-19 pandemic years”.

“This will indicate if there is a genuine increase in the baseline number of URTI. We may be just observing the ‘normal’ baseline trend in the number of URTI cases in the year. Building immunity can reduce the severity of illness and also accelerates recovery. There is evidence that immunity does offer cross-protection against different strains of certain viruses,” she added.

Although the MOH Weekly Infectious Diseases Bulletin shows that the number of cases in the pre-Covid-19 year of 2019 recorded at polyclinics was higher than in the corresponding weeks of 2022 and 2023 after the mask-down announcements, the climb in the number of cases was not as steep.

For instance, average daily consultations at the polyclinics in the week of the masks-down announcement last August were 1,998. The figure rose 2.8 per cent to 2,054 a week later. But the number spiked to 3,514 six weeks after – a 22.7 per cent increase from the 2,865 daily cases the week before. This rise was mirrored in February 2023 when it was announced that masks were not needed on public transport.

The 2019 daily cases in corresponding weeks, although much higher, fluctuated only between 1 per cent and 7 per cent.

A spokesman for MOH said it routinely monitors a range of acute respiratory infection (ARI) indicators in the community and at hospitals, including polyclinic and emergency department attendances, and hospital admissions for ARI.

She said that under the National ARI Surveillance Programme, which monitors infection trends and the distribution of respiratory viruses in the community, a proportion of ARI cases at polyclinics is tested for a range of respiratory pathogens.

“Safe management measures (SMMs), including mask wearing, practised during the Covid-19 pandemic have helped reduce the transmission of Covid-19 and other respiratory infections. These measures do not weaken the immune system. The increase in the number of ARI cases, when compared with the period when SMMs were in place, is due largely to the resumption of social activity. The current average daily number of polyclinic attendances for ARIs has returned to pre-pandemic levels,” the spokesman added.

Dr Leong said: “Without exposure, the level of antibodies falls. Without a Covid-19 year, repeated exposures to the same viruses, even without falling sick, would keep the antibodies up, and would confer significant protection and herd immunity. In other words, the best way to prevent infection by the same virus would be frequent exposure.”

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