Coronavirus Vaccines

Experts address current issues regarding vaccines

An hour-long webinar last Thursday brought together local and international experts to discuss the latest medical and scientific findings about the coronavirus. Here are some highlights.


Q What should individuals with anaphylactic reactions do since they cannot receive the Covid-19 vaccination for now?

A As the Singapore vaccination programme is still being ramped up, vaccination guidelines will continue to be updated. Current vaccination recommendations are unlikely to be the finalised versions. There are also other vaccine candidates which are being reviewed. With time, there should be options for everyone to be vaccinated.

Q Should individuals with chronic but stable medical conditions get vaccinated?

A Yes, they are encouraged to get vaccinated. But if you have a newly diagnosed serious medical condition, and are receiving intense treatment or frequent medication, then you should postpone the vaccination until your condition stabilises.

Q Can I get vaccinated if I have had surgery in my limbs?

A Yes, you can get vaccinated. But local site reactions are quite common for mRNA vaccines, so it will be good to wait for the post-surgical healing process to be over before proceeding with the vaccination.


Q Different trials in different countries have reported different efficacy levels for Sinovac. Is this of concern?

A Calculating efficacy is a highly complex affair. There is an interplay of different factors such as participation numbers, prevalence and rate of transmission of Covid-19, the presence and effectiveness of existing public health measures as well as testing strategies.

Hence, trials that have been done cannot be compared head to head as even the recruitment of trial participants has been very different. For instance, Indonesia recruited only the general public while Brazil recruited only healthcare workers. Trials have also been done under very different pandemic situations, with places like Brazil experiencing a very rampant outbreak. Hence, these factors will also influence vaccine efficacy, and official data will be needed from Sinovac before conclusions can be drawn.

The efficacy of mRNA vaccines is also very high and that has unfortunately set the bar unfairly high for other vaccine candidates. A successful vaccine is one that is safe and can achieve an efficacy of more than 50 per cent.

A version of this article appeared in the print edition of The Straits Times on March 29, 2021, with the headline 'Experts address current issues regarding vaccines'. Subscribe