To boost or not to boost? Make the right choice
by TMR / pic by MUHD AMIN NAHARUL
SINCE the beginning of 2021, Malaysians have been lining up at vaccination centres to ensure that they get their primary vaccinations.
While there was some hesitancy in the beginning, the take-up rate of the vaccine soon ramped up and as of Jan 4, latest update from the Health Ministry shows that the country has fully vaccinated 97.7% of its eligible adults (aged 18 and above) and 87.7% of those aged 12 to 17.
But the fight against the virus continues and a few months after proudly displaying photos of ourselves getting our jabs, we are heading to clinics again — this time to get our booster shots.
Many health authorities had earlier assured us that boosters were not needed, so why the U-turn?
“We are learning as we go along. Initially, it was thought that having two shots was enough. But research continues and with new data, we now know that the protective effect (or neutralising anti-body levels) for all vaccines tend to drop with time.
“That’s why the government and other authorities around the world are now proposing booster shots,” International Medical University School of Medicine division of medicine head and infectious disease consultant Dr James Koh.
This should not come as a surprise, he said, as most vaccines have boosters. For instance, the Hepatitis B vaccine has three doses — the second and third ones being the boosters, anti-tetanus jabs should be boosted once every ten years and the pneumococcal vaccine that protects against pneumonia, once every five years.
“It’s not unique to the Covid-19 vaccine. We might not be familiar with vaccine boosters as Malaysians do not typically go for vaccinations,” Dr Koh added, highlighting that although it is recommended that we get the influenza vaccine every year, very few do.
An Urgent Awakening
For Malaysians in particular, the need for boosters became urgent as the majority of our population, especially in the earlier phases, had taken Sinovac as their primary vaccination.
Local statistics from the Real-World Evaluation of Covid-19 Vaccines under the Malaysia National Covid-19 Immunisation Programme show that Sinovac’s protection against Covid-19 infection fell from 76% in the first two months of being fully vaccinated to just 28% in months three to five. International studies corroborate this.
“At three months, research shows that the neutralising antibody level in Sinovac was less than 50% and at six months, it was almost undetectable,” he added.
For the Pfizer and AstraZeneca vaccines, lowered efficacy starts to show at six months. It is important therefore to get the booster shot which essentially reawakens our immunity systems to start producing antibodies.
“This booster shot is not the end-game. There will be a next booster and a next — we don’t know how many but we definitely know this will not be the last,” Dr Koh explained.
The safety of mixing vaccines has also brought about hesitancy. In early November 2021, the Center for Disease Control and Prevention gave the green light to mix and match the different vaccines for our boosters.
However, a statement in July by World Health Organisation chief scientist Soumya Swaminathan stated that data on mix-and-match was still unavailable, still circulates.
For the record, she had later clarified that: “Individuals should not decide for themselves, public health agencies can, based on available data.”
And the available data has been growing. Evidence from countries that have been rolling out a mix-and-match system have shown good results. Singapore’s studies have shown a 72% reduction in infection risk when mixing the Pfizer primary vaccination with a Moderna booster compared to 62% for those who used Pfizer for their first, second and booster shots.
Data from the Chilean Health Ministry shows that the mix of a Sinovac primary vaccination with a booster of Pfizer resulted in a 95% effective rate against the virus. This was a big jump compared to using three doses of Sinovac, which showed a 74% effectiveness.
Dr Koh encourages everyone to take their boosters no matter the mix as it is more dangerous not to take a booster.
“It is better to get any booster than to have none at all. With Sinovac, it will just mean that you will probably need another booster sooner than later,” he said.
Are there those who should not take the booster? No, he said as anyone who was cleared to take the first two doses, is able to take the booster.
For those with diminished immunity such as those living with HIV/AIDS, those who had organ transplants or cancer patients, booster shots may actually be a fourth shot.
“Some might have had to get three doses in the beginning to stimulate their immune systems to produce antibodies. For them, their booster shot would actually be the fourth jab,” he said, adding that boosters are also perfectly safe in such cases.
The landscape continues to change with new variants such as the Omicron emerging.
“There’s still much to be known about the new strain. Preliminary findings suggest that Omicron is five times more transmissible than the original virus, while Delta was twice as transmissible as the original.
“That means with Delta, one infected person can infect two persons, while with Omicron, one infected person can infect five persons,” he explained.
Omicron is also three times higher in terms of reinfection — that means you can get it again and again. However, so far the data shows that symptoms are mild among adults while children are experiencing heavier symptoms.
The silver lining is that the death rate hasn’t gone up yet although it will only be closer to the end of the year before there is enough data to make any conclusions.
Some promising news is that Pfizer and BioNTech have just released a statement that three doses of the Pfizer vaccine still provide protection against Omicron in terms of developing severe disease.
To Boost or Not to Boost?
“Vaccines will continue to be updated. Even if you do not take a booster now, you will still need to have one in the future. In the meantime, the current boosters are still effective,” Dr Koh concluded.
To boost or not to boost? Make the right choice.