The Current Covid Situation And Booster Doses — Prof Dr Moy Foong Ming

Malaysians should value the freedom they currently enjoy, and should take their booster doses when they are available. Go for the first vaccine brand being offered, and get yourself and your loved ones protected. 

The health minister and health director-general have warned us that there may be new Covid-19 wave soon. Clinicians treating Covid-19 patients have also highlighted that hospital admissions and intensive care unit (ICU) usage are on the rise.

Are they being overly worried about Malaysia’s Covid-19 situation? Why is this happening when the overall vaccination rate has almost reached 80 per cent?  

The R naught (representing the number of people that a Covid-positive person can infect) was 0.87 on October 22, and it has been fluctuating below 1.0 until November 11.

Since then, the R naught value has increased and has hovered between 1.0 and 1.05, with the latest value at 1.0 on November 22.  An R naught of less than 1.0 is the most ideal value.

The number of daily cases dropped to 4,343 on November 7, but there was no further improvement. Instead, the number of daily cases increased to 6,380 on November 18, and has fluctuated between 4,000 and more than 6,000 since then.

Concurrently, ICU usage in states like Selangor, Kuala Lumpur, Kelantan, Penang, Putrajaya has exceeded 75 per cent.  

Despite the full vaccination rate of 76.6 per cent as of October 23, we notice that the situation is not further improved. Why is this happening?

Firstly, with the opening of most economic sectors, and interstate travel allowed again, the people’s mobility has increased. When mobility is increased, and if there is poor compliance with Covid-19 SOPs, this will cause transmissions among the unvaccinated and the vaccinated. 

Vaccination is also not 100 per cent effective in the prevention of transmission; it merely prevents severe disease, hospitaliations and deaths.  

This situation might worsen, as evidence has shown that vaccine effectiveness will wane over time. The latest data from Real-World Evaluation of Covid-19 Vaccines Under the Malaysia National Covid-19 Immunisation Programme (RECoVaM) shows that vaccine effectiveness will reduce to 68 per cent (Pfizer) and 28 per cent (Sinovac) in three to five months after full vaccination has ben completed.

Individuals vaccinated with Pfizer and Sinovac vaccines after three to five months were 79 per cent and 28 per cent less likely to be admitted to ICU respectively, while 91 per cent and 76 per cent respectively are less likely to die from Covid-19. 

These figures prove that vaccine effectiveness will fade over time, with the Sinovac vaccine waning effect at 50 per cent, the acceptable cut-off value for vaccine effectiveness.

Concurrently, the analysis on deaths among patients who took different vaccines showed that there are 6.0 deaths per one million population for those who took the AstraZeneca vaccine, 9.8 deaths per one million population for those who took the Pfizer vaccine, and 34 deaths per one million population for those who took the Sinovac vaccine. 

This showed that the waning effects of vaccines, especially the Sinovac vaccine, might result in deaths. Of course, the findings could be influenced by the fact that the patients who were surveyed are mostly senior citizens.  

This is why the Ministry of Health (MOH) is aggressively pushing for booster doses among senior citizens and high-risk groups with comorbidities, especially those who took the Sinovac vaccine. 

However, the uptake for the booster dose has been poor, due to the fact that only the Pfizer vaccine is currently offered. 

There are worries about side effects from taking a booster dose that is of a different brand from the first two doses. Mix-and-match vaccination, especially for booster doses, is being practised in many countries. For example, Indonesia, Singapore and Chile have mixed Sinovac with Pfizer, while Thailand and Cambodia have mixed Sinovac with AstraZeneca. 

European countries have also been mixing their available vaccines (Pfizer, AstraZeneca and Moderna). There have been no known severe side effects reported.  

The main reason for mixing Sinovac with other vaccines is because it will produce up to 94 to 95 per cent vaccine effectiveness, while using Sinovac as the booster will only provide 75 per cent vaccine effectiveness. 

It is unfortunate that there is a lot of unverified information about the mixing of Sinovac with Pfizer that is being circulated on social media. This has resulted in many individuals being wrongly influenced, and have declined the Pfizer vaccine as a booster dose.  

This will jeopardise the MOH’s efforts in providing additional protection. Malaysia cannot afford to have another lockdown, and the health care system cannot afford to be overburdened with severely infected patients who require ICU admission. 

We should be aware of a new Covid-19 wave happening in some European countries, which has resulted in new lockdowns in Austria and the Netherlands.

Malaysians should value the freedom they currently enjoy, and should take their booster doses when they are available. Go for the first vaccine brand being offered, and get yourself and your loved ones protected. 

We hope that the MOH can also expedite the inclusion of Sinovac vaccines in the National Covid-19 Immunisation Programme (PICK).  We must do our part so that the situation can remain under control. 

Prof Dr Moy Foong Ming is Professor of Epidemiology at the Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya.

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