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Saturday, 30 Jul, 2022

'I caught Covid-19 three times': S'poreans reinfected with virus see milder symptoms (Straits Times Premium)

SINGAPORE - A young man in his 20s has had Covid-19 three times.

A mother had her third pregnancy bookended by Covid-19 infections.

A local comedienne tested positive twice within three months. The third time around, she was too exhausted to go through another test.

Two-and-a-half years into the pandemic, many in Singapore have contracted the virus.

But a number of Singaporeans have caught Covid-19 more than once, raising questions about the chances of reinfection as the Omicron strain and its subvariants continue to wend their way around the world.

Infectious diseases specialists say that newer versions of the virus have become better at evading the body's immune response, even though reinfections tend to be milder than the first infection.

Figures revealed in Parliament in April showed that from Nov 1 last year to March 25 this year, there were 8,845 cases of reinfection in Singapore. By late March, Singapore had recorded about 1.06 million Covid-19 cases since the start of the pandemic, Ministry of Health (MOH) figures show. To date, there are close to 1.7 million Covid-19 cases, according to the MOH website.

Infectious diseases expert Paul Tambyah tells The Straits Times that Covid-19 reinfections are "extremely rare" and estimates that more than 99 per cent of patients in Singapore do not get reinfected.

Still, getting Covid-19 more than once can come as a shock.

Mr A. Tan, 29, who works in the medical sector, has caught the virus thrice. The first time was in March 2020, about a week before the two-month circuit breaker started. There were only around 900 cases of Covid-19 in Singapore then.

Coming down with a fever and cough, he found out he was infected after taking a polymerase chain reaction (PCR) test. The bachelor, who declines to use his full name, recalls how worried his mother, a widow and housewife in her 60s, was.

"There were no vaccines then. My biggest concern was spreading the virus to her," he adds. Mr Tan, who has four siblings, lives with his mother and a sister.

After testing positive on March 31, 2020, he was quarantined at Mount Alvernia Hospital. He did not know then that he would not leave his hospital room for two months.

His Covid-19 symptoms faded by the fifth day, but he continued to test positive via PCR swabbing for 61 days before he was discharged.

In the hospital, he shared a room with three other patients, who came in one after the other. They were foreign workers with whom he is still in contact.

Dr Asok Kurup, an infectious disease physician at Mount Elizabeth Hospital, says the highly sensitive PCR test, which detects genetic fragments of the Sars-CoV-2 virus, can "show up as positive for weeks, even months".

These Covid-19 sufferers are shedding dead viral components picked up by the swab test, and their infection is no longer contagious, he says.

"Most patients are no longer infectious after seven days," he adds.

Mr Tan also suffered from long Covid, where the virus' effects linger, with symptoms such as fatigue and weakness. He lost his sense of smell for eight months.

When lightning strikes thrice

Eighteen months after first contracting Covid-19, Mr Tan developed a sore throat, fever and cough. A PCR swab test on Sept 27 last year confirmed his suspicions.

He says: "I was a bit shocked when I got reinfected. I had had no known contact with infected individuals. My mother cried again. She didn't know what reinfection meant. Was it like dengue, for instance, where reinfections can be quite severe? She felt very sorry for me."

He isolated at home and tested negative using an antigen rapid test (ART) kit on Day 10. This time, his symptoms lasted only two days.

Five months later, on Feb 25 this year, he tested positive again. This time, he had only a sore throat which cleared up overnight. He thinks he probably got it after a visit from a relative who had recently recovered from Covid-19.

Mr Tan, who is healthy and not in a high-risk demographic, laments that he feels "quite unlucky" that he caught the virus thrice in three years.

His infections coincided with the periods when the Alpha, then Delta and Omicron strains became dominant around the world.

"After the second infection, I thought, what are the odds? When I got it the third time, I wondered, what's going on?" says Mr Tan, who was fully vaccinated by February last year and received a booster shot in January this year.

"The silver lining in all of this is that it did get better each time. We have already moved in the direction of endemic Covid-19. I think people still need to take precautions, but it's probably a matter of time before one gets it."

He is glad, at least, that he did not spread the virus to his mother and sister at home, though both caught Covid-19 about two months ago and have since recovered.

Milder but more frequent?

Indeed, Covid-19 reinfections tend to be milder, says Professor Tambyah, a senior consultant at National University Hospital's (NUH) division of infectious diseases and Professor of Medicine at NUS Yong Loo Lin School of Medicine. He adds that this probably extends to infections from future Covid-19 variants.

"All the data suggests that Covid-19 reinfections are milder than the first episode. This is true of most viruses, with the notable exception of dengue," he says. "All known human viruses mutate to become more transmissible and less virulent. As such, the new variants are more likely to be intrinsically milder in the infections that they cause."

Other infectious diseases specialists note, however, that the risk of reinfection is elevated today, which in turn poses more health risks, given the high transmissibility of Omicron, the current dominant strain, and its subvariants.

Dr Ruklanthi de Alwis, deputy director of the Centre for Outbreak Preparedness at Duke-NUS Medical School, notes that immunity levels are waning in highly vaccinated Singapore, with protection by antibodies declining from both vaccination and from previous Covid-19 infection.

In other countries, she says, "we're seeing that the reinfection period can get shorter".

Earlier this month, the Australian state of New South Wales revised the Covid-19 reinfection period from 12 to four weeks. The health authorities cited the surge of the Omicron BA.4 and BA.5 subvariants in the local community in their decision.

Dr Kurup agrees: "If the previous Covid-19 infection was a long time ago, there may be a great difference between the strains and people can have symptoms again."

He says the ongoing development of new vaccines - such as a pan-sarbecovirus vaccine, targeted at different coronaviruses; or mucosal vaccines, which could trigger protective immune responses at predominant sites of infection like the nose - could offer additional protection against Covid-19.

Feeling vulnerable

Comedienne Sharul Channa, 35, has had Covid-19 twice, maybe thrice.

In a show with fellow entertainer Kumar, The Sharul and Kumar Show 2, this month, she joked about having enough post-infection immunity to donate antibodies.

"I've had Covid three times. In case anyone hasn't got their booster, you can suck my blood," she quipped.

She says she has not had a chance to get a booster shot yet, given her repeated infections over the past eight months.

In November last year and February this year, she experienced symptoms such as a sore throat, cough, runny nose, tiredness and fever, and tested positive both times on PCR tests at a general practitioner's clinic.

Earlier this month, before her show at the KC Arts Centre, she developed similar symptoms, but tested negative using an ART. Too tired for further testing, she chose to self-isolate.

Days after she emerged from isolation, she checked herself into a hospital when she had sharp pains in her lower abdomen. She attributed it to too much sneezing and coughing. Her doctor diagnosed it as "a viral infection", which was likely her third brush with Covid-19.

Dr de Alwis says it is not uncommon to test negative for Covid-19 using an ART, while testing positive with a PCR test at the same time.

The PCR test, which detects the nucleic acid component of the virus, is more sensitive than the ART, which detects proteins produced by actively replicating virus. However, while PCR swabs can pick up low, inactive amounts of the virus, ARTs are a better indicator of infectiousness, says Dr de Alwis.

Dr Kurup adds that maintaining healthy habits like regular exercise and a nutritious diet, as well as keeping chronic diseases like diabetes under control, can reduce the risk of infection and reinfection.

In the meantime, Channa is focusing on building up her immunity with vitamin C supplements and probiotics from her doctor. She recently resumed her 10km walks and gym workouts, which are less intensive than before.

"I can't afford to get Covid-19 again. I need to be careful," she says.

'The fear of getting Covid-19 is more crippling than Covid-19'

When she caught Covid-19 on two occasions, Mrs Winnie Tomlinson, 41, was more concerned about her family's quarantine arrangements than her own health.

Last September, the Singaporean church worker returned from a trip to the United States with her husband, an American director at an international business school here, and their two sons, Noah, four, and David, five.

She tested positive during their quarantine at a hotel. Minutes before her Covid-19 test result came through, she had taken a pregnancy test as the couple had been trying for a third child.

She recalls: "I found out that I was pregnant practically at the same time I tested positive for Covid-19. It was bittersweet, but we were determined not to let Covid-19 cloud the joy of pregnancy.

"For us, the uncertainty surrounding how long we would be in quarantine, as well as the stress of having PCR tests for our young children, were a lot more stress-inducing than Covid-19 itself."

In the end, she was transferred to another hotel and later, a hospital. There, the doctor instructed her to recover at home instead, together with the rest of her family. Noah tested positive for Covid-19 while in home quarantine, though he was asymptomatic.

In June this year, three weeks after her daughter Maria was born, Mrs Tomlinson's husband Austin came down with Covid-19, which spread to the rest of the family, as well as to their domestic helper.

Mrs Tomlinson and Noah have thus caught Covid-19 twice, and she suspects her three-month-old baby, who had a high fever at one point, may also have been infected. She has not had her booster shot since falling pregnant with Covid-19, while her husband got his a month before he was infected.

Both Mrs Tomlinson's bouts of Covid-19, where she had symptoms like chills, fever and a cold, were mild.

She says: "I've come to realise that the fear of getting Covid-19 is more crippling than Covid-19 itself. The stress is a lot less now, but it's not mentally healthy as a society.

"We've done our part to be socially responsible. Let's move on."

Originally posted on Straits Times (Premium): 'I caught Covid-19 three times': S'poreans reinfected with virus see milder symptoms