Up-to-date vaccine stockpile vital, say experts

KUALA LUMPUR:  While booster jabs remain a critical tool to protect people from death or hospitalisation due to Covid-19, health experts stress the importance of ensuring that Malaysia's vaccine stockpile is up-to-date to effectively tackle new virus variants. 

They also renewed calls for a masking mandate, especially in high-risk and populated areas, such as health facilities, malls and schools, amid the escalating number of cases. 

Public health expert and epidemiologist Datuk Dr Zainal Ariffin Omar said a low uptake of booster shots might render many people, especially older adults and those with underlying medical conditions, susceptible to severe infections.

He expressed concern that lower vaccination rates left the population less prepared if a newer, more concerning variant of the virus emerged, fuelling another surge in cases and hospitalisations.

"The recent increase in Covid-19 cases in the country is real and worrying. Furthermore, vaccine-induced and natural immunities are waning, and the poor uptake of booster doses adds to the concern," he told the New Straits Times yesterday.

Dr Zainal also urged the Health Ministry to be more active and aggressive in encouraging people to voluntarily opt for booster shots.

He added that mandating booster doses might not be necessary at the moment, but people should take extra precautions, such as masking in public places, avoiding crowded areas, and practising self-quarantine if they showed symptoms.

He also raised concern over anti Covid-19 vaccination groups that have flooded social media, calling for the Health Ministry to counter these "false narratives" aggressively.

On Wednesday, it was reported that the number of Covid-19 cases had risen from 6,796 to 12,757 in the 49th epidemiological week, in line with the global increase in infections.

Epidemiologist and health informatician Datuk Dr Awang Bulgiba Awang Mahmud said relying solely on vaccines to protect against infection was insufficient. 

Vaccines, he noted, worked best against severe disease and less so against infection, so non-pharmaceutical interventions (NPIs) should also be used during these wavelets. 

This, he said, included wearing good-fitting, high-quality masks (N95, KN95, KF94, FFP2 standard, or better), especially in crowded indoor environments, and practicing good hygiene.

He also said that boosters should not be made mandatory, and repeated boosters would be challenging to implement without a structured adult immunisation programme. 

He further said it was no longer possible to expect the first versions of vaccines to provide effective protection against symptomatic infections, as the current variants were antigenically different from the Wuhan variant.

"If we want to use vaccination as a strategy, then it would be wise to update our Covid-19 vaccines. 

"Malaysia has been slow to obtain the latest versions of vaccines.

"The expired stocks of Covid-19 vaccines were reported to be replaced with the bivalent versions of those vaccines."

Dr Awang Bulgiba noted that bivalent vaccines were actually the second version of the original vaccines, but they were no longer considered to be the latest version.

"It would have been considered an updated version in 2022, but it is no longer recommended in 2023, as the World Health Organisation reported on Dec 13 in the 'Statement on the antigen composition of Covid-19 vaccines'."

He said it would be more prudent for Malaysia to obtain the latest monovalent versions based on more current Omicron sub-variants in circulation.

"This is to avoid the problem of immunological imprinting and improve the humoral and cellular immune response to current variants.

"It looks like we have gone from the monovalent vaccines (Wuhan variant) to bivalent vaccines (Wuhan + an Omicron sub-variant) to monovalent (an Omicron sub-variant). This is to be expected as the virus evolves," he explained.

When the newer Covid-19 vaccine versions become available in Malaysia (monovalent against an Omicron sub-variant), it would be a good idea for the most vulnerable persons (elderly, immunocompromised, those with chronic illnesses, etc.) to get boosted, he said.  

He added that Covid-19 antigen test kits tended to be less sensitive in the first couple of days of infection, which might result in a false negative test.

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