Is 90% Adult Vaccination Rate The Magic Number?— Dr Musa Mohd Nordin & Dr Mohammad Farhan Rusli

We should be looking at total population vaccination rates rather than adult vaccination rates.

It looks like the magic number of 90 per cent touted by the prime minister and the health minister may soon be celebrated with inter-state crossings. This is the proportion of adults above 18 years old who have been fully immunised with Covid-19 vaccines.

This “adult herd immunity” concept is unique to Malaysia, and we are surprised that none from among the infectious diseases and public health fraternity has challenged its validity. Will it confer indirect protection to the unvaccinated segment of the population? Most certainly not!

In an earlier piece, we concurred with a pediatrician colleague, Dr Amar Singh, that we should be instead be emphasising and mainstreaming data on total population vaccination rates rather than adult vaccination rates.

At best, 90 per cent adult vaccination coverage translates to 65 per cent vaccinated population, which is insufficient to protect the unimmunised population of the country.

This would have been possible to protect against the original Wuhan strain or maybe the Alpha Variant of Concern (VOC). In the face of the raging Delta VOC, which is highly transmissible with a Reproduction Number (Ro) of 5-7, we need to immunise at least 90 per cent of our total population in order to confer indirect protection to the unimmunised 10 per cent cohort.

Only then we can consider transitioning from the pandemic to the endemic phase. We must learn from the experience of our southern neighbours, who are now experiencing a surge of Covid-19 cases despite achieving a vaccination uptake of 83 per cent.

235 (84 per cent) of the 281 hospitalised patients in Singapore (October 6, 2021) are above 60 years old. They have begun to offer third doses of mRNA vaccines to their elders. We have yet to begin, and even then, it is only an optional requirement.

This is of much concern because 41.6 per cent of our population are recipients of the inactivated vaccine which has been shown to be associated with more admissions into ICUs and mortalities, and by extension, more breakthrough infections and hospitalisations.

The other population segment of concern are children and adolescents below 18 years old. Up until October 8, we have vaccinated 68.5 per cent of 12-17 year old adolescents with one dose and 4.7 per cent with two doses. This needs to be ramped up further in our efforts to boost population immunity.

Even then, this is inadequate. We need to begin to look at new data on the safety and efficacy of mRNA vaccines for the younger age group. The United States’ Food and Drug Administration (FDA) will be reviewing the mRNA vaccine for children aged 5-11 years old on October 26. 

There has been an explosive increase in the number of children infected and dying from Covid-19 up until mid-September 2021, compared to the previous year.

The American Academy of Pediatrics have reported that 100 children have died from Covid-19 in the recent five weeks. 

The Delta variant has caused a six to eightfold increase in the Case Fatality Rate of children as shown in the table below.

While in the transition phase, there are three other indicators apart from vaccination coverage, which must be carefully considered in our re-opening strategy.

We alluded to these indicators briefly in this newspaper report and will discuss them in more detail in a forthcoming article.

  • This is the personal opinion of the writer or publication and does not necessarily represent the views of CodeBlue.

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