The health minister said while Sinovac was effective against the worst effects of the disease, it wanes (loses effectiveness) quickly compared to other vaccines.

Khairy said hence, the booster shot was offered within three months of the last dose of the Sinovac vaccine, while those who got the Pfizer and AstraZeneca vaccines would be given booster jabs six months later.

“That’s why we want you to take whatever booster is on offer,” he said in a tweet.

Khairy attached an infographic of admissions of category four and five patients at the Sungai Buloh Hospital, where admission of Sinovac-vaccinated patients was higher than others.

In 11 weeks, the admissions involving Sinovac patients increased fourfold from 48 cases on epidemiology (epid) week 35 to 165 cases in epid week 45.

The highest recorded Pfizer-shot patients were on epid week 45, with 24 cases. The lowest cases were recorded for those who received AstraZeneca shots, with an average of 10 cases per week.

As of yesterday, Pfizer remains the highest administered vaccine at 53.5%, followed by Sinovac (38.3%), AstraZeneca (7.8%) and CanSino (0.4%).

Currently, the booster vaccine is being given to seniors aged above 60 and frontliners from the medical and national security-related agencies.

Come Monday, those who want to get their booster dose can do so by walking into participating private clinics.