SINGAPORE - Over the course of eight months, John (not his real name) contracted Covid-19 twice.
The 37-year-old permanent resident, who was infected with the Delta Plus variant while he was overseas in May last year, fell victim again - this time to the Omicron variant - while travelling to Singapore last month under the Vaccinated Travel Lane scheme.
Three days after he arrived here on Dec 10, John was informed that a fellow flight passenger tested positive for the virus.
John was asked to undergo a polymerase chain reaction test which came back positive.
The news left him dismayed, with memories of the challenges his family faced when they were all infected in May still fresh in his mind.
"The Delta Plus infection left me with body aches and a fever that lasted three days, and it took me a while to get better," he said.
"I was very worried for my wife as she experienced loss of appetite, extreme fatigue, body aches and fever for five days. The infection weakened her and she took two weeks to fully recover."
Their daughter was asymptomatic.
First reportedly discovered in Europe in March last year, Delta Plus is a subvariant of Delta and people infected with it exhibit similar symptoms.
John's 60-year-old mother-in-law and 76-year-old grandmother, who were also infected in May, managed to make a full recovery. Both were fully vaccinated while John and his wife were not then.
He said: "With the Omicron variant, I had only a scratchy throat, but I was thankful my wife and child were still overseas as they too might have been infected again if they were with me."
He was admitted to the National Centre for Infectious Diseases (NCID) for eight days before he was discharged after testing negative.
John said he is thankful his recent infection was mild, unlike his previous one in May. This time, his symptoms subsided after four days.
John, who completed two doses of a Covid-19 vaccine in October and November last year, believes the milder nature of Omicron and being fully inoculated offered him more protection against severe illness when he was reinfected.
Dr Choy Chiaw Yee, a consultant at NCID, noted that the risk of hospitalisation for those infected with Omicron is about one-third that of Delta, and Omicron seems to cause fewer deaths as well.
"Although this may seem promising, it is important to note that the Omicron variant is noted to be more transmissible than the Delta variant, and also more likely to infect people who previously had Covid-19," she said.
Dr Choy highlighted that vaccination is vitally important for people to guard against severe illness, with an 81 per cent reduction in the risk of hospitalisation for those who have three doses of a vaccine compared with unvaccinated Omicron cases.
"The risk of hospitalisation is lower for Omicron cases with symptomatic or asymptomatic infection after the second or third dose of vaccine," she noted.
While Omicron seems to cause a milder infection than Delta, Dr Choy cautions that its transmissibility is a cause for concern.
She said: "If the number of Omicron cases continue to rise unchecked, the number of hospitalised patients and deaths will correspondingly rise and still put a burden on the healthcare system.
"It is therefore vitally important for the public to complete their vaccination by taking their booster dose if they have not done so."
Singapore recorded 692 new cases of the Omicron variant on Saturday, a decrease from the 832 recorded a day earlier.
More than 290,000 Covid-19 cases have been reported so far.
Some Omicron patients hit by night sweats; no such cases seen locally
As the number of individuals infected with Omicron continues to rise worldwide, some are reporting a unique symptom associated with the Covid-19 variant - night sweats.
According to the Mayo Clinic, night sweats are repeated episodes of extreme perspiration that may soak your clothes or bedding.
They are commonly associated with conditions such as anxiety disorders, thyroid disease or cancer.
While Omicron patients in South Africa and Britain have complained of night sweats, this has yet to be reported among local cases.
Dr Choy Chiaw Yee, consultant at the National Centre for Infectious Diseases, said night sweats remain a rare symptom of the Omicron variant.
She said that based on early observation, individuals with the Omicron variant experience flu-like symptoms such as headache, fever, cough, general body pains and fatigue.
"Individuals with the Delta variant experience symptoms such as fever, loss of smell or taste, cough, shortness of breath and diarrhoea," she added.
Dr Hsu Li Yang, an infectious diseases expert at the National University of Singapore's Saw Swee Hock School of Public Health, noted that night sweats were hardly reported with previous variants of the virus and that this is an uncommon symptom among those infected with Omicron.
"In general, most infected persons will have mild cold or flu-like symptoms. Vaccinated persons in particular will be either asymptomatic or have mild symptoms.
"The Omicron variant is more transmissible and has a shorter incubation period, but thankfully, it is a less virulent variant, even for unvaccinated individuals," he said.