KUALA LUMPUR, July 28 — Experts have cautioned against stretching the interval between the first and second doses of the Pfizer Covid-19 vaccine beyond four weeks, Khairy Jamaluddin said in Parliament today.

Citing expert advice from the Vaccine Selection Technical Working Group, the coordinating minister for the National Immunisation Programme (NIP) explained that there were genuine concerns over the efficacy rate of protection accorded by just a single dose of the Pfizer vaccine against the aggressive Delta variant of the virus.

“For Pfizer, we have thought of extending the interval of dosing. They are suggesting that we extend it to six weeks, eight weeks.

“There is only one issue to that, before the spread of the variant of concern Delta, we did agree to extend six to eight weeks for Pfizer. But with the Delta variant, we found that the efficacy rate of one dose of Pfizer is only about 30 per cent.

“With that, the technical working group has made the recommendation to NIP not to extend the interval and maintained it at four weeks,” Khairy said in the Dewan Rakyat this afternoon.

The Pfizer vaccine is the most widely available brand among the different vaccines approved for use in Malaysia. In recent weeks, the Delta variant has emerged as the most dominant and infectious strain, according to data from the Health Ministry.

Khairy was responding to several Opposition MPs who asked the government to ramp up the NIP and concentrate on providing the first dose of vaccines to as many people as possible. They suggested extending the interval between doses as means to widen the coverage.

Among them was Bukit Mertajam MP Steven Sim asked Khairy if it is possible to provide a clear appointment date for those who had registered for vaccination.

But Khairy explained that the government could not push forward the vaccine appointments because of uncertainty in the delivery dates of the supplies from Pfizer.

“The problem I have, Bukit Mertajam, is Pfizer. Pfizer would only give their delivery schedule for the coming two weeks and this is the practice worldwide.

“When they would give me the delivery schedule for two weeks, I am not sure how many of the vaccines would arrive, when I’m not sure of how much would arrive, I cannot make a projection of when I can give appointment to all because I don’t know whether Pfizer will give two million this week, 1.4 million next week, in two weeks’ time or three million in two weeks’ time, that is the problem now.

“When there is clarity in terms of the delivery, then we can push out as many appointments as possible,” Khairy said.

Sim then asked why the government did not purchase the 14 million doses of Sinovac vaccine by Malaysian pharmaceutical firm Pharmaniaga Berhad instead.

Khairy replied that the government had concluded the Sinovac deal earlier. He explained that buying more would increase the government’s overall Covid-19 budget and that serious consideration is needed before this can be done.

He added this issue will likely be tabled later in the coming regular parliamentary session on Budget 2022.

Deputy Prime Minister Datuk Seri Ismail Sabri Yaakob previously said on July 21 that 14 million doses of Sinovac vaccine will be sold by Pharmaniaga Bhd to interested states and private companies from this month until September.