‘Follow SOP even after vaccination’

Experts: It’ll take time to find out whether vaccine can prevent transmission

PETALING JAYA: People must continue following standard operating procedures such as masking up and physical distancing – even after being vaccinated – until more data is available on how effective the Covid-19 vaccines are, say experts.

Universiti Malaya epidemiologist Prof Datuk Dr Awang Bulgiba Awang Mahmud said while vaccines offer a person direct protection from the virus, it remains to be seen if they can adequately prevent spread of the disease.

“To prove that the vaccine can prevent transmission would take a longer time and is a little more complicated.

“One has to use direct measures, such as epidemiological studies, and indirect measures, such as checking viral load and swab tests, to demonstrate the prevention of transmission,” he said.

He added that vaccine trials were aimed at “low-hanging fruit” in that they sought to reduce symptomatic infection.

“In other words, the vaccinated person is likely to be protected against symptomatic infection to a large degree, but we do not have sufficient data on the prevention of transmission.

“This data will likely be available in the coming months as more people get vaccinated and studies are done,” he said.

He added that individuals who received their first dose also faced the risk of getting infected before sufficient antibodies were produced.

“However, by the time of the second dose, there would be some protection. After the second dose, there will be a short period before this protection is boosted to a level which could last for some time,” he said.

He added that while it was unnecessary for those waiting for their second jab to undergo home quarantine, they must still follow the SOP.

Prof Dr Moy Foong Ming of Universiti Malaya’s Department of Social and Preventive Medicine said someone who had been vaccinated could still be an asymptomatic carrier.

“As such, vaccinated people may still be able to spread Covid-19 to others,” she said, adding that it was also possible that they may get infected despite being vaccinated with the first dose.

“That’s why experts are insisting that everyone receive the second dose within a key time frame. We need to get both doses within two to three weeks,” she said.

Researchers, she added, did not know yet just how long the immunity given by the current vaccines would last.

“Until more is known about how long the protection lasts – and against which variants – we need to maintain the SOP to keep everyone safe.

“However, trials show that even if a vaccinated person develops Covid-19 symptoms, he or she is much less likely to develop severe condition,” she said.

Health director-general Tan Sri Dr Noor Hisham Abdullah said all preventive public health measures would still be in place even after the nationwide vaccination exercise kicks off next week.

“At this point, there is still a lack of data on whether the vaccination reduces transmission of the infection.

“Therefore, we still need to adhere to the current preventive measures until we have enough data to prove otherwise,” he said.

The World Health Organisation said it was “too early” to tell whether Covid-19 vaccines would provide long-term protection against the virus and that additional research was needed.

“However, it’s encouraging that available data suggests that most people who recover from Covid-19 develop an immune response which provides at least some protection against reinfection,” it said.

Until more is known about how long the protection lasts – and against which variants – we need to maintain the SOP to keep everyone safe.

Prof Dr Moy Foong Ming