Malaysia shortens second AstraZeneca vaccine dose interval from 9 to 6 weeks starting 1st October

Health Minister Khairy Jamaluddin has announced that Malaysia will be reducing the vaccine dose interval for AstraZeneca to just 6 weeks. The shorter interval between the first and second dose will be implemented starting 1st October 2021.

According to Khairy, the decision to reduce the vaccine dose interval is to provide convenience to individuals that have gotten the first dose of the AstraZeneca vaccine. AstraZeneca has the longest dose interval among all two-dose vaccines under the National Immunisation Programme. As a comparison, both Pfizer and Sinovac vaccines have a shorter 3-week interval. On top of that, an individual is only considered fully vaccinated two weeks after receiving their second shot.

When Malaysia started administering the AstraZeneca vaccine in May, the original plan was to implement a 12-week interval as it offered a higher 82.4% efficacy. However, due to rising COVID-19 cases in July, it was then decided to reduce the dosing interval to 9 weeks so that more individuals can get fully vaccinated earlier.

The World Health Organisation (WHO)’s Strategic Advisory Group of Experts on Immunisation (SAGE) recommends an interval of 8 to 12 weeks for AstraZeneca. According to the WHO, longer dose intervals within the 8 to 12 weeks range are associated with greater vaccine efficacy. Based on the Ministry of Health’s guideline for AstraZeneca, a shorter interval of 28 days may be observed when rapid protection is required.

Besides Malaysia, Australia has also followed a shorter 6-week dose interval for AstraZeneca in the state of Victoria.