AS most people in the Klang Valley still have not had their second vaccine dose, it is tough to expect a reasonable degree of herd immunity, say health experts.
This is even if all adult residents in the area – comprising 6.1 million people – have received at least one vaccine dose by Aug 1, the aim of the Covid-19 Immunisation Task Force’s Operation Surge Capacity.
Universiti Malaya epidemiologist Prof Datuk Dr Awang Bulgiba Awang Mahmud says this is because a single dose will not confer sufficient protection.
“There are two types of protection which are caused by vaccination – direct protection and transmission protection.
“Direct protection reduces the severity of infection while transmission protection reduces spread. A high degree of direct protection should logically offer quite good transmission protection as there will be reduced viral load and hence fewer viruses are likely to be spread by an infected person. Herd immunity largely depends on transmission protection,” he explains.
But most Covid-19 vaccines already in use by most countries depend on two doses to achieve some degree of direct protection. A reasonable degree of direct protection is also only achieved two weeks after the second dose.
“As such, I don’t think we can expect a reasonable degree of population level immunity by Aug 1 in the Klang Valley as most have not had their second dose,” Dr Awang Bulgiba says.
With variants of concern like Delta and Beta among the population, he points out that it’s also not enough to rely on a single vaccine dose to guard against these strains.
Dr Awang Bulgiba says to avoid a sharp increase in new cases, non-pharmaceutical interventions (measures that don’t involve medicines, like wearing masks and the ban on inter-district travel) should be eased gradually and only when there is evidence of reduced transmission.
“We should not rely on vaccination numbers alone, far fewer numbers of people have only received single doses,” he says.
He advises the public to adjust their expectations of a “normal” life with preparations for a long drawn-out battle against Covid-19.
“The practical thing is to complete vaccination as soon as we can to achieve some level of population immunity and monitor it.
We should also retain non-pharmaceutical interventions to some degree and relax restrictions carefully.
“Keeping our finger on the pulse of the pandemic is especially crucial, and that requires having good data,” he adds.
Dr Awang Bulgiba says that having experts like epidemiologists, behavioural scientists and clinicians who can advise the authorities is most critical.
“In Malaysia, there is ample capacity to give advice but there is little capacity to accept good advice. This needs to change,” he stresses.
Universiti Putra Malaysia medical epidemiologist Dr Malina Osman says it would be considered safe for fully vaccinated employees to return physically to the workplace – “But strict SOPs should be continued until the situation is considered safe for us to ease some of the restrictions,” she says.
Dr Malina also believes that freedom of movement cannot be allowed for Klang Valley residents even if all adults have received at least one dose of the vaccine.
“This is because the healthcare system in the Klang Valley and in most states is at a very critical level. Once the healthcare system can serve both Covid-19 and non-Covid-19 patients and is no longer in a compromised state, then more freedom of movement can be allowed.
“But this should be recommended only for those who have completed two doses of vaccines. We have to have two complete doses to produce some level of herd immunity,” she says.