QUESTIONS have arisen on whether vaccines developed for the original Covid-19 virus are effective against new strains, such as the South African B.1.351 and UK B.1.1.7 variants, which have now made it into Malaysia.

The questions come as the government rolls out phase two of the Covid-19 vaccination programme today.

Under the second phase, the government is targeting the inoculation 9.4 million vaccine recipients comprising high-risk groups such as the elderly, those with chronic health conditions and disabled people.

On Friday, Health Minister Dr Adham Baba said the vaccines to be used by Malaysia are effective in protecting the recipients against the UK and South African variants.

Science, Technology and Innovation Minister Khairy Jamaluddin also tried to reassure Malaysians that the authorities will study data on the efficacy of vaccines against newer variants of the virus.

A total of 17 cases of the South African and five cases of the UK variants have been reported nationwide to date.

Studies have shown that these particular strains have a considerable level of resistance towards antibodies.

The presence of the E484K mutation in the lineage gives the strains the ability to evade certain antibodies, causing concern among scientists.

The South African variant is also said to contain mutations such as N501Y, which helps the virus latch on more tightly to human cells, while K417N helps the virus bind to cells.

Some findings suggest that the variant has the potential to reinfect people who have already had Covid-19.

According to the British Medical Journal (BMJ), the mutation is thought to allow the virus to escape some of the body’s immune response.

“Vaccines developed against the original virus have also been found to be less effective against the South African variant,” the journal said in an article entitled Covid-19: Where are we on vaccines and variants?

This has raised questions on the efficacy of vaccines, developed to induce protection against the original form of the virus, against the newer mutated lineages of the virus.

Nonetheless, this does not mean that the vaccines are completely ineffective against the variant, but the level of protection offered could be lower than the original variant of the virus.

Meanwhile, in Neutralisation of SARS-CoV-2 Variants B.1.429 and B.1.351, an article about the Californian and South African variants published in the New England Journal of Medicine, said the “magnitude of resistance seen with the South African variant is of greater concern with respect to current vaccines”.

Another article Cross-Reactive Neutralising Antibody Responses Elicited by SARS-CoV-2 501Y.V2 (B.1.351) published in the same journal said vaccines built on the spike protein of 501Y.V2 may be promising candidates to elicit cross-reactive neutralising antibody responses against the virus.

At this juncture, it is still unclear which vaccines work best against this variant, which is considered among the most challenging to date.

According to a clinical trial report published in the New England Journal of Medicine in March, two doses of the AstraZeneca vaccine did not show protection against mild-to-moderate infection of the South African variant. Its efficacy was said to be 10.4%.

South Africa has also halted the use of the vaccine.

As for Pfizer-BioNTech vaccine, more definitive studies have yet to be carried out.

It was reported that the jab has showed early signs of preventing disease in a small subset of study volunteers in South Africa, from where the concerning B.1.351 variant originated.

However, a recent study said that the variant is able to evade the protection provided by the vaccine, as the prevalence rate of the variant in those vaccinated with two doses of the shot was 5.4% compared to 0.7% in the unvaccinated.

Meanwhile, the Susceptibility of Circulating SARS-CoV-2 Variants to Neutralisation study – which looked into the effectiveness of the Sinopharm and Sinovac vaccines against the variant— said the variant showed more resistance to vaccine serum than the wild-type virus while the UK variant showed little resistance to the neutralising activity of the vaccine serum.

For the UK variant, various studies have shown that vaccines such as Pfizer-BioNTech, Moderna, Sputnik V, AstraZeneca, Johnson and Johnson and Novavax have been effective.

The variant which emerged in the UK December last year has now become dominant in the US as well.

The UK variant is said to be about 60% more contagious and 67% more deadly than the original form of the virus. – April 19, 2021.