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Experts: More data needed on Delta

KUALA LUMPUR: THE highly contagious Delta and Beta Covid-19 variants have triggered a new and dangerous phase in the pandemic, which may see an increasing number of cases, raise the herd immunity threshold and derail Malaysia's exit plan from the total lockdown. 

Experts called for the government to maintain stringent control over existing standard operating procedures (SOP), beef up border controls and impose a mandatory 21-day quarantine on everyone entering the country. 

They urged the authorities to be on the watch for the new Delta plus variant, or AY.1, despite it not being detected in Malaysia yet, amid concerns over vaccine efficacy against the virus.

Virologist and Universiti Putra Malaysia Microbiology Unit head Associate Professor Dr Chee Hui Yee said that while Malaysia should be concerned about the Delta variants, more data and research were needed to understand the mutation and its risks. 

"The Delta plus is a sub-lineage of the Delta variant first detected in India, which has acquired the spike protein mutation called K417N (also found in the Beta variant first identified in South Africa)," she told the New Straits Times

The World Health Organisation (WHO) has listed Delta, Beta, Gamma and Alpha as "variants of concern" (VoC), associated with higher transmissibility and severity of the disease, with potential implications for acquired immunity or the effectiveness of current vaccines.

Up to June 19, Malaysia has identified 167 VoC cases involving 137 of the Beta variant, 21 of the Delta variant, and nine of the Alpha variant, as well as 16 Variants of Interest (VoI) cases. 

While scientists are studying the Delta plus variant, India has classified it as a VoC because it spreads and binds with greater ease to lung cells and is potentially resistant to monoclonal antibody therapy, a potent intravenous infusion of antibodies to neutralise the virus.

Chee said it was too early to declare it as a VoC but could perhaps be viewed as a VoI (which causes community transmission, multiple Covid-19 cases/clusters, or has been detected in countries).

"There is no need to overreact since the Delta plus variant has not been declared a VoC by the World Health Organisation. But we must keep a close watch on it by conducting more extensive studies to correlate the hospitalisation, treatment, severity of symptoms, vaccine effectiveness and whether the current laboratory detection kit can detect it."

Up to June 18, 205 cases of the Delta plus variant have been detected worldwide (including in India, Portugal, Switzerland, Japan, Poland, Nepal, China, Canada, Turkey and Russia), with the United States and United Kingdom reporting more than half the known number.

In the UK, its first five cases, sequenced on April 26, were contacts of individuals who had travelled from or transited through Nepal and Turkey.

About 40 samples were detected from six districts in three states in India — Maharashtra, Kerala and Madhya Pradesh. The earliest case in India is from a sample taken on April 5.

Chee said a study on the Pfizer-BioNTech and AstraZeneca vaccines revealed that both were effective against hospitalisation from the Delta variant.

However, she said it could not determine their effectiveness against the new Delta plus mutation.

"More studies need to be done to determine the effectiveness of other vaccines used in Malaysia against the Delta variant (and its mutations) and what type of booster vaccine is needed."

She added that the race was on between variant and vaccine.

She called for the Covid-19 National Immunisation Programme to be accelerated.

"Besides that, we need to strictly follow the SOP, impose a higher fine on SOP violators and conduct active SARS-CoV-2 genome surveillance. The government needs to know what are the circulating variants.

"It also needs to have a contingency plan if it decides that it is best to prolong the lockdown."

Manipal University College Malaysia Community and Occupational Medicine Professor Dr G. Jayakumar said Malaysia must boost genome sequencing to better arm itself in responding to new Covid-19 variants.

He said the country's screening rate was low, which makes it difficult to identify VoCs.

"Malaysia has to be concerned about the new variants as the WHO has reported that the Delta variant has spread to 92 countries. 

"Early reports indicate that the Delta variant is more transmissible, as well as infects and replicates faster than the Alpha, Beta and Gamma variants.  

"It is reported that the Delta variant is about 50 to 60 per cent more transmissible than the Alpha variant.

"Delta variants may increase the threshold for herd immunity to a higher percentage. It can evade the body's natural disease-fighting immunity more efficiently."

He said patients infected with the Delta variant often complained of headache, sore throat, and a runny nose, replacing cough and loss of taste or smell as the most Covid-19 common symptoms.

"The Delta plus variant is new. It may have potential resistance to treatment by monoclonal antibodies."

Monoclonal antibodies, he said, were proteins produced by human bodies to defend against diseases,

He said these proteins could be created in a laboratory and tailor-made to treat a disease.

Nevertheless, Dr Jayakumar said it was too early to accurately predict the efficacy of Covid-19 vaccines against the Delta and Delta plus variants. 

"Data from Public Health England reported that Pfizer's vaccine is 96 per cent effective, while the AstraZeneca vaccine is 92 per cent effective against hospitalisations after two doses. These results are comparable with efficacy against the Alpha variant."

Dr Jayakumar said more data and time were needed to determine whether mix-and-match vaccine approaches were more effective against the variants.  

Universiti Malaya Occupational and Public Health Expert Professor Dr Victor Hoe urged the government to tighten border controls.

Hoe said all returnees and visitors entering Malaysia must undergo between 14 and 21 days of mandatory quarantine to curb the transmission of the new variant. 

Currently, only returnees from Nepal, Bangladesh, Pakistan and Sri Lanka undergo a mandatory quarantine of 21 days.

Hoe said the main VoC in the country was the Beta variant, which is more transmissible than the original SARS-CoV-2 virus.

Vaccines, he said, were less effective against the Beta variant.

Hoe suggested the government prohibit all indoor activities that require removing of face masks as an additional SOP.

Former Malaysian Medical Association president Datuk Dr N.K.S. Tharmaseelan said that so long as people took both vaccine doses, there would be protection against the Delta variant.

"It will reduce its impact and morbidity rate. Immunocompromised individuals or those with comorbidities, such as hypertension and diabetes, are more at risk.  

"People must be fully vaccinated to ensure protection against the virus.

"Researchers had said people were less likely to develop enough antibody response to protect against the Delta variant after receiving a single dose, compared with the previously dominant variant."

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