Forum: Timely booster shots key to ensuring vaccination rate doesn't sink below desired level

Since Singapore outlined the road map to living with Covid-19, the world has been watching how we actually live with Covid-19 as an endemic disease.

The multi-ministry task force on Covid-19 had warned that we should be prepared for more cases as the country reopens for business.

Vaccination is at present the best possible defence against Covid-19.

But it has been reported that the efficacy of the vaccines decreases over time.

If the efficacy of the vaccines indeed wanes over time, then the so-called national vaccination rate risks becoming a variable figure, unless all vaccinated people receive their booster shots when needed.

Otherwise, the vaccination rate risks sinking below the desired threshold for herd immunity.

With the easing of restrictions nationwide, the speed of transmission of the Delta variant will increase because of our high population density.

A potential compromise in the effective vaccination rate (after accounting for boosters when due) as the Delta variant spreads with reopening is one adverse outcome we must avoid.

As a matter of principle, in public health policy, we should err on the side of caution, especially with a pandemic like Covid-19, which is still evolving and not well understood.

It appears that if our primary target of keeping fatalities low is met, and as long as cases are mild or asymptomatic in those who have been fully vaccinated, we are content to have restrictions further eased. Still, the fact that infected individuals who are vaccinated are often asymptomatic may not mean that they will not have any longer-term health issues 10 years down the road.

Christopher Ng

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