KUALA LUMPUR: Malaysia's actual Covid-19 infection rate is likely far higher than reported as many people cannot distinguish symptoms of the dominant Omicron variant from those of other variants.
Experts believe this is one of the key reasons behind the spike in brought-in-dead (BID) cases. The Health Ministry had said 91 per cent of BID victims did not know they had contracted the SARS-CoV-2 virus.
They said the elderly, those with comorbidities and the unvaccinated were at high risk of infection and reiterated calls for them to get vaccinated and boosted to minimise community spread.
University Malaya Medical Centre public health medicine specialist Associate Professor Dr Rafdzah Ahmad Zaki said the Covid-19 fatality rate for the unvaccinated was 46 times higher than those who had received a booster dose.
She said Health Ministry statistics showed that the death rate for the unvaccinated was 9.1 deaths per 100,000 people, while the rates for those who had completed primary vaccination and received a booster dose was 0.7 per 100,000 and 0.2 per 200,000, respectively.
"This means the death rate for the unvaccinated is about 46 times higher than those who have been boosted. While among those who only completed two doses, it is four times higher than those who received the booster jab.
"This suggests that vaccination does help with the situation and booster doses provide extra protection," the head of the UM Centre for Epidemiology and Evidence-based Practice told the New Straits Times.
She said symptomatic patients from high-risk groups should be extra cautious.
"Although the number of cases is much higher than before due to the Omicron wave, the fatality rate remains low and our healthcare facilities are not as overloaded and strained as before.
"Regular monitoring is required for high-risk groups as their vital signs may deteriorate quickly."
Epidemiologist Professor Datuk Dr Awang Bulgiba Awang Mahmud of Universiti Malaya said people tend to assume Omicron symptoms would be the same as previous variants like Delta, hence they did not notice the signs of infection until it was too late.
He said those infected with Omicron might experience runny nose, nasal congestion, cough, fatigue and night sweats without loss of smell or taste, making them assume they only had a common upper respiratory tract infection.
It has been reported that loss of smell and taste happens less with Omicron infections.
"Infected persons may brush off their symptoms as just the common cold or a minor cough, so they do not get tested. And when they deteriorate rapidly, they end up being brought in dead.
"The Omicron variant can also be more virulent for some people, resulting in faster deterioration."
He said the surge in BID cases could be caused by far and inaccessible medical facilities, like in remote areas, resulting in patients deteriorating at home before they could seek treatment.
"The Health Ministry also said the recent rise in BID cases was caused by backlog deaths.
"It is noteworthy that three-quarters of all tests being carried out are RTK-Ag tests.
"There is a strong possibility people are testing negative (false negative) in early tests, so they assume they are not infected until their condition deteriorates."
Dr Awang Bulgiba, who is also the Science, Technology and Innovation Ministry's Covid-19 Epidemiological Analysis and Strategies Task Force chairman, said BID cases were an indicator that community spread was far worse than officially reported figures.
"Infection figures depend very much on testing strategies. If we test less, then infection numbers may fall, but deaths need to be reported and recorded regardless of testing strategies.
"It is perhaps a more reliable indicator than infection numbers alone. So when deaths go up, accompanied by increasing positivity rates, this indicates that community spread is far higher than the officially reported figures.
"Test positivity rates are at more than 10 per cent now, meaning community spread is higher than official figures."
He said even though the Omicron variant had more antibody-evading properties than past variants, it caused less severe illness not so much because symptoms were "mild", but because of wide-spread population immunity.
He said when someone is administered a booster dose, especially with an mRNA vaccine, the rise in antibodies is sufficient to stop most infections within two months of the shot.
He said the enhanced cellular immunity from vaccination was also reactivated much quicker in vaccinated and boosted persons and that helped prevent severe illness with Omicron infections, while the same could not be said for unvaccinated persons.
"One of the unfortunate myths surrounding Omicron is that it causes 'mild' illness. It is not mild, it is less severe despite all the immune-escaping mechanisms the variant appears to have. There lies the paradox.
"Unlike the Delta variant, Omicron appears to result in activated interferon signalling, which activates a whole host of immune responses in people, including cellular immunity.
"But in unvaccinated persons, this direct protection from vaccines is not available and their cellular responses are probably not as good, so Omicron can still cause severe illness.
"It is, therefore, crucial for the government to increase booster uptake to cover 80 per cent of the population to dampen an Omicron-fuelled wave."
Public health expert and epidemiologist Datuk Dr Zainal Ariffin Omar advised the public to get tested for Covid-19 if they experience headaches, sore throat, runny nose, breathlessness, body pain and fever.
"These should not be ignored as we are putting the lives of people around us, including unvaccinated children and the elderly, at risk. Eligible adults should get their Covid-19 booster jabs soon."
He said people should also learn to use pulse oximeters to measure blood oxygen levels.
A pulse oximeter is an electronic device that clips onto a finger to measure heart rate and oxygen levels in the red blood cells, usually used to monitor patients with lung disease.