KUALA LUMPUR: The Pfizer-BioNTech manufactured vaccine, COMIRNATY (Concentrate for Dispersion for Injection), requires double doses to produce long-lasting immunity against the coronavirus in the recipient's body.
Health director-general Tan Sri Dr Noor Hisham Abdullah, in a statement today, said a delay in getting the second jab could delay the optimum production of antibodies.
"The efficiency rate of COMIRNATY vaccine was reported as 94.6 per cent (N= 36,621) in peventing SARS CoV2 infections based on the third phase of the clinical trial, in which, two vaccine doses are administered at an interval of 21 days (the permitted time interval is up to 42 days).
"However, the Strategic Advisory Group of Experts on Immunisation (SAGE) from the World Health Organisation (WHO) has advised for the second dose to be administered within 21-28 days after the first dose.
"Based on clinical trial observations, the COMIRNATY vaccine started demonstrating effectiveness since Day 12 after the first dose was administered and achieved 89 per cent effectiveness between Day 14 and Day 21, which is the period when the second dose is injected.
"However, the long-term effectiveness of a single dose of the COMIRNATY vaccine remains unknown because recipients in the clinical trial received two vaccine shots between 19 to 42 days.
"Therefore, it is important to note that a significant increase in antibodies can provide long-term effectiveness after an individual receives the second dose," he said.
Dr Noor Hisham also assured that the ministry is conducting regular monitoring on the vaccines that are used in the National Covid-19 Immunisation Programme through the quality product monitoring programme and pharmacovigilance to guarantee the quality, safety and efficacy of the vaccines.