I read senior health correspondent Salma Khalik's article with concern (Eligible individuals who refuse vaccine endanger themselves and others, Feb 24).

While I agree with the short-term safety and efficacy data of the vaccine, as well as the importance of hitting the "critical threshold" to achieve herd immunity, I think having a veiled threat by suggesting punitive action against "non-vaccinators" in the article is hardly the way to go. Open dialogue and directly addressing people's concerns would probably be more effective.

Little is known about the vaccine's long-term safety.

Studying the mechanism of the vaccine itself, the mRNA encodes for a spike protein to be produced, which then binds to the ACE-2 receptor to stimulate the immune response. This same mechanism has been implicated in the long-term cardiac complications of Covid-19.

While it is true that none of the published studies has demonstrated increased cardiovascular mortality after the Covid-19 vaccination, this is at present more a function of a lack of long-term data rather than an endorsement of its long-term safety. Until the long-term trials have concluded, I do not think we can brush this off lightly.

I also cannot agree with her statement that "no matter how you look at it, it would be better to get vaccinated than to risk getting the disease". I think we have to consider the risk-benefit ratio in the different subsets of the population.

We know that in a fit and healthy young person, the risk of mortality from Covid-19 is incredibly low. But in the elderly population with multiple comorbidities, the risk of severe disease is extremely high.

Hence for the younger, healthy population, the risk-benefit ratio of being vaccinated skews towards "risk", especially with so much unknown about the vaccine's long-term safety.

I would like to end by saying that despite all my dissent, most of my immediate family members have been vaccinated to protect the elderly at home.

I am writing to make it clear that at present, little is known about the long-term safety of the vaccine and in choosing to be vaccinated, people should be well informed not just of the benefits, but also of the risks of the unknown.

Lee Chun Yii