Covid-19: Delay in getting second dose of Pfizer vaccine may slow optimum antibody build-up, says Health DG

PETALING JAYA: Delays in receiving the second dose of the Pfizer-BioNTech Covid-19 vaccine may slow the optimum build-up of antibodies, says Tan Sri Dr Noor Hisham Abdullah (pic).

“The drastic increase in the antibody’s ability to provide effectiveness for a person in the long-term is after the second dose.

“A delay in getting the second dose may slow the optimum production of antibodies, ” the Health director-general said Wednesday (March 17).

He added that at the moment, the long-term effectiveness of the vaccine after the first dose is unknown as clinical studies are done on those who received the second dose after 19 to 42 days.

He said the ministry took note of recent issues raised over the need for taking the second dose of the vaccine which provides 94.6% efficacy in preventing Covid-19 (SARS CoV2) infections.

He added that based on third phase clinical trials, the second dose of the vaccine was administered after 21 days although a gap of up to 42 days was permissible.

“However, the World Health Organisation’s Strategic Advisory Group of Experts on Immunisation (SAGE) has recommended that the second dose be given between 21 and 28 days after the first dose, ” he said.

Dr Noor Hisham added that based on observations during clinical trials, the effectiveness of the vaccine begins 12 days after the first dose and achieves an efficacy rate of about 89% between 14 and 21 days.

The second dose of Pfizer-BioNTech vaccinations will be administered beginning Wednesday.

On Monday (March 15), Health Minister Datuk Seri Dr Adham Baba said the second dose was for those who had already received their initial dose of this vaccine when the first phase of the vaccination started on Feb 24.

Prime Minister Tan Sri Muhyiddin Yassin was the first to receive the Pfizer vaccine on Feb 24 when the national immunisation programme began its rollout.

The programme will involve the immunisation of 70% of the population under three phases, starting with frontliners from now till April.

The second phase is from April to August for those in high-risk groups, while the third phase from May to February 2022 are for adults aged 18 and above.

Khairy Jamaluddin, who is coordinating minister for the programme, had said the immunisation programme is expected to be completed before the end of this year, ahead of its projected completion date in February next year.