Focus on herd immunity first, boosters can come later, say experts
KUALA LUMPUR: The debate over booster shots of the Covid-19 vaccine is heating up globally over concerns that the contagious Delta variant is capable of infecting fully vaccinated people. The World Health Organization (WHO) argues that it may be too early to push for Covid-19 booster shots, especially when many…
KUALA LUMPUR: The debate over booster shots of the Covid-19 vaccine is heating up globally over concerns that the contagious Delta variant is capable of infecting fully vaccinated people.
The World Health Organization (WHO) argues that it may be too early to push for Covid-19 booster shots, especially when many people around the world have not even received their first dose.
On Aug 26, health director-general Dr Noor Hisham Abdullah said that the booster shots for those who have completed their Covid-19 vaccination will not curb the highly contagious Delta variant.
He said the current Covid-19 vaccines used in Malaysia have proven effective against the Delta variant, which resulted in the reduction of hospital admissions, intensive care unit (ICU) bed usage and ventilators for its patients.
Currently, there are five vaccines approved under the national Covid-19 immunisation programme (PICK), namely Pfizer-BioNTech, Sinovac, AstraZeneca, CanSino, and the Janssen vaccine of Johnson & Johnson.
Concentrate on the unvaccinated
Malaysian Public Health Physicians’ Association (PPPKAM) president Dr Zainal Ariffin Omar said PICK should prioritise getting as many people as possible to be vaccinated before considering booster shots.
He said giving a booster shot to increase the efficacy of someone who already has protection should not be prioritised over those who have zero protection.
“There is no need to rush into giving booster shots to ward off the more transmissible Delta strain amid concerns over the mutation which has been categorised as a variant of concern (VoC).
“Mass vaccination must be prioritised before consideration can be given for a booster shot. No one will be safe until everyone is,” he told Bernama.
As at Aug 28, 61.1% of the country’s population or 14,297,962 individuals have completed both doses of the Covid-19 vaccine, according to the Covid-19 vaccine supply access guarantee special committee (JKJAV).
Zainal said some countries provided the third dose for their citizens because they have sufficient supply and have achieved herd immunity.
But in Malaysia, he said there are still many people who have yet to be vaccinated.
“Some states, like Kedah and Kelantan, have not even reached 40% for the fully vaccinated. Some states also have been facing shortages of the vaccine.
“We have to focus on delivering at least two shots to prevent the spread of VoCs. Yes, we have new variants now. We might have other variants coming soon.
“But to achieve herd immunity, we must get as many people as possible to be vaccinated. Later on, when there is enough data and vaccines, only then should we consider giving them booster shots,” he said.
Mixing vaccines
With the spread of VoCs, many countries are considering giving booster shots or a third dose to prevent the mutation of the virus in the future.
Oxford-AstraZeneca vaccine co-developer Prof Dr Teresa Lambe said this is not yet necessary as it is more important to prioritise the first dose for as many people as possible globally.
“That’s actually one of the areas I am working on in the lab. What we have done is to give a third dose of the Oxford-AstraZeneca vaccine to a small number of people, in the hundreds.
“What we are looking to see is whether the immune response is boosted.
“We have seen that with the third shot. But my interest will be to get first doses across the world to individuals who haven’t had any vaccine yet before we consider booster shots.
“There is an onus on us to make sure the world is protected before we start looking to deliver boosters,” she said in a keynote address at the Third International Conference of Pharmacy and Health Sciences 2021 held virtually.
On getting the different brands of the second dose in Covid-19 vaccines, Lambe said this did produce potent immune responses in mixing-and-matching regimes.
The time frame for the second Pfizer shot is three weeks after the first dose. For AstraZeneca, it is 9-12 weeks after the first dose.
“I have been involved in some studies looking at administering the Pfizer-BioNTech jab first or the ChaAdOx1 nCoV-19 (Oxford-AstraZeneca) first, then giving the other second dose,” said Lambe.
“One regime is slightly more reactogenic but the immune responses in the mixed regime do look good,” she said.
Zainal said there is a need to have proper planning from the government whether to give mixed vaccines and booster shots to prevent the VoC of the virus.
“Right now, achieving herd immunity through the two-dose vaccines should be the priority. It might be confusing for people if we implement mixed vaccines or booster shots for now.
“If the government decides to kick-start such programmes, they should make preparations and do proper planning to purchase enough vaccines for the boosters or mixed regime. This will also avoid supply shortages,” he said.
Lambe advised the public to trust the regulators and take whatever brand of approved Covid-19 vaccine that is offered to them without judging them.
“For me, you need to look at the real-world effectiveness data, trust the regulators and trust the safety monitoring board to make recommendations for the best vaccine for the people in your country.
“Take the vaccine you were offered. Get that vaccine in your arm, make yourself safe and make the world safe,” she said. — Free Malaysia Today