Sinovac stocks at the moment in most PPV's are the last batch. Full 14m doses already almost to the end of delivery. Hence remaining stocks reserve for 2nd dose. Now on can expect Pfizer for those going 1st dose.

Tbh, its Sinovac to be the safer option when it comes to medicine interference. Pfizer (mRNA) and AZ (Viral Vector) are considered new kid on the block with lesser long term safety data on interactions with pharmacological substances. Sinovac's CoronaVac (inactivated virus) vaccine is a traditional platform as old as time can get when it comes to vaccines.

But since your doc said so. How to go against him, maybe a 2nd opinion?

It's already announced in the news regarding Sinovac. Initially the supply was for 2m doses a month till November. But Pharmaniaga managed to speed up deliveries and complete all deliveries by this month. Hence why 1H 2021 almost all PPVs were giving out Sinovac. Pfizer deliveries are only ramping up right now as we speak. However there is a plan B to increase Sinovac's order in the event Pfizer/AZ or other incoming vaccine supply disruption. Although unlikely to happen but thats the back up plan as we have quick access for Sinovac if needed.

Sadly due to media spin and misunderstanding, people are getting the wrong idea Sinovac being stopped by KKM due effectiveness issue.

If one were to scrutinize Sinovac's data from Thailand where only 618 out of 677k healthcare workers infected, it actually performed better than Pfizer in Malaysia where 3100 healthcare workers caught covid from 245k who received it. But not sure why Thai health authority is panicking, maybe they should see Malaysia's data first haha.

Like you said, take wtv comes first is best. Most likely we all need a 3rd booster shot somewhere down the line. That time people can choose la what they want as supplies will be a lot irregardless of the type.