by S BIRRUNTHA / pic by TMR FILE

EXPERTS say it is better to not jump the gun when it comes to booster shots, as there appear to be benefits to waiting longer to administer the third dose of the Covid-19 vaccine.

Sinovac Biotech Co Ltd senior director of overseas business Meng Weining said this is because a prolonged period (period before a booster) can induce higher levels of antibodies.

He also noted that a person may get a stronger immune response if they wait a little longer before getting a booster shot.

“Current data have suggested that the immunity reached when a booster shot is given after a year is more robust than that achieved after six months.

“However, for countries still suffering with high levels of Covid-19, they need to really consider a balance of early boosters or a later booster.

“This is especially for the elderly and high-risk people, we still suggest the booster be given roughly six months after the second dose,” he said in a webinar session organised by Pharmaniaga Bhd yesterday.

Meng added that the Covid-19 vaccines continue to be safe and effective against severe disease, as well as hospitalisation.

He said all three of the authorised vaccines provide good protection for at least six months after initial vaccination and likely longer, before waning gradually.

On vaccinating children, Meng said his research showed their immunity lasted longer than adults and the elderly.

Therefore, he emphasised that booster shots for children may not be needed until much later compared to adults.

Nevertheless, Meng noted that research by Chinese vaccine maker Sinovac has found that after receiving a booster shot, immunity appears to be stronger and longer lasting than that gained after a full two-dose course.

He said studies have shown that the level of antibodies produced by their CoronaVac vaccine appears to wane after six months.

“After two doses, the body already has a memory of immunity, so when a booster is given, we see both a high and stable level of antibodies.

“Even six months after the third dose, we see that the level of antibodies is still much higher than the peak after their second dose, so that is also encouraging for us,” he added.

The Ministry of Health (MoH) has targeted to administer the third dose of Covid-19 vaccine to about 8.75 million individuals, to increase the level of protection of the vulnerable against the epidemic.

Health Minister Khairy Jamaluddin Abu Bakar said yesterday that the number of recipients of the third dose includes healthcare frontliners, safety and defence personnel.

He added that the number also includes patients who are immunocompromised, the elderly and individuals living or working in care centres, as well as individuals with comorbidities.

Meanwhile, Pharmaniaga head of biologic and vaccine specialist Dr Ajit Pal Singh opined that although the priority of Covid-19 booster shots is given to high-risk group members, everyone must receive a third dose moving forward.

He said a fully vaccinated individual’s antibody levels will start to wane after six to eight months of getting both jabs, adding that this may cause an outbreak of cases in the country.

On that note, Dr Ajit Pal also stressed that mixing Covid-19 vaccines is not recommended currently for booster shots, as well as for the primary intake of two doses.

He said recent scientific studies have shown that mixing Covid-19 vaccines could cause one to experience greater side effects compared to receiving one type of vaccine.

Speaking on vaccine hesitancy, Millennium Institute in Immunology and Immunotherapy of Chile professor and director Dr Alexis M Kalergis said scientists and doctors are advised to explain the effectiveness of vaccines to the public in simple terms.

He added that the scientific community must work together with educational institutions, such as universities to educate the public on vaccine efficacy.

“In Chile, the scientific community, universities and the government shared scientific evidence on vaccine efficacy using social media platforms as most people get their information from there.

“We told scientists and medical doctors to be careful when they speak about vaccines so as not to confuse the public,” he noted.

Sharing similar thoughts during the webinar session, Bio Farma Indonesia operational director Dr M Rahman Roestan said understanding and reducing public concerns regarding the Covid-19 vaccines is of utmost importance.

He said effective strategies can be formulated later after identifying the factors for vaccine hesitancy to encourage the public to accept the jabs.

According to him, in Indonesia, a section of the public was initially worried about the halal status of the Sinovac vaccine.

“So, what we did was consult the Indonesian Ulama council, madrasahs and other Islamic authorities to get their help to enlighten the public.

“The Ulama council inspected the materials and the equipment used in the production of the Sinovac vaccine before providing us the halal certification. That way, the halal issue was resolved,” he explained.