Malaysia Needs Dengue Vaccine But Will The People Accept It?

It reads: AWAS!!! TERDAPAT KES KEMATIAN DARI DENGGI DI KAWASAN INI (WARNING!!! THERE HAS BEEN A DEATH DUE TO DENGUE IN THIS AREA).

Dengue, a sometimes fatal viral disease, is no stranger to Malaysians and its visitors. It does not play favourites, affecting people from every walk of life who chance on an infected Aedes aegypti mosquito, which transmits the viruses that cause dengue.

The infection is seeing a surge in cases this year in Malaysia and elsewhere, thanks to a number of factors including human complacency, climate change and El Nino, according to experts. El Nino, a weather phenomenon resulting in hot weather and less precipitation, is expected to continue in Malaysia until next month. 

The number of deaths due to dengue has also increased in Malaysia.

As such, health authorities and experts have hailed the recently launched dengue vaccine by pharmaceutical company Takeda, to be marketed under the brand name Qdenga, as a breakthrough in the fight against dengue. It should have garnered excitement and be the talk of the town, or at least among general practitioners who will be dispensing the vaccine. 

But till today, very few clinics or members of the public know about the vaccine. And even if they knew, the public may not be as excited as infectious disease experts to get the vaccine.

Vaccine hesitancy, confirmed by research, has grown in the country and region due to the misinformation surrounding COVID-19 vaccines. To complicate matters, the first dengue vaccine, Dengvaxia by Sanofi Pasteur, had an unfortunate rollout in the Philippines in 2016 as it was found the vaccine could worsen a dengue infection if the vaccinated person had never had dengue before. 

Dengvaxia never received approval in Malaysia and is not available here.

Takeda head of medical affairs for India and Southeast Asia Dr Goh Choo Beng told Bernama after the media launch of the Qdenga dengue vaccine that they are aware that they may be facing their biggest obstacle.

“After approval, (social acceptance) is the next challenge,” he said. 

 

Malaysia has set a target to reduce dengue cases by five percent per year. It is also aiming for zero deaths from dengue by 2030, in keeping with the World Health Organisation’s targets.

In the past, dengue management has involved managing the mosquito population, or vector control, by reducing or eliminating the breeding grounds for the Aedes aegypti mosquito, increasing community education and fogging, as well as mandatory notification to public health authorities and quarantine. 

For the past five years, the government has also been using mosquitoes carrying the Wolbachia bacteria, which causes them to be sterile or cause female mosquitoes to lay unhealthy eggs, to control the population.

Despite such efforts, dengue cases have been on the increase. Last year saw 123,133 cases and 100 deaths from dengue-related complications. This year, experts have observed a worrying trend. Rather than ebbing after reaching a four-year peak in 2023, cases seem to be on an upward trajectory with 67,137 cases reported in the first 23 weeks of 2024 compared to 51,331 cases for the same period in 2023, showing an increase of 30.7 percent, according to the Ministry of Health. 

As for deaths, 48 were reported in the first 23 weeks of this year compared with 37 fatalities for the same period last year.

This increase is especially worrying as dengue outbreaks tend to peak and wane on a four-year cycle in most countries. However, cases in Malaysia are not showing signs of abating. 

“We have actually seen an increase in dengue cases. It’s worrying. The last peak was in 2019 and then 2023, and now we see (a rise in cases in) 2024 (which is when cases are supposed to start going down). So we’re not sure how much 2024 will be,” said Prof Datuk Dr Zulkifli Ismail, chairman of Dengue Prevention Advocacy Malaysia. 

At the media launch of Qdenga on June 11, Takeda’s Dr Goh said the vaccine has been undergoing trials for almost five years with no major adverse events recorded. He said no one needs to be previously infected with dengue or undergo a test to determine a previous infection before getting the vaccine. 

The company reported the vaccine has prevented symptomatic infection in 80 percent of cases in 12 months after vaccination, and hospitalisation in 90 percent of cases in 18 months after vaccination.

Qdenga has been approved in more than 30 countries including European Union nations, the United Kingdom, Brazil, Argentina, Thailand, Vietnam and Indonesia. Malaysia’s Drug Control Authority gave conditional approval to the vaccine in February this year. 

One other benefit of the vaccine is herd immunity, of sorts. Mosquitoes spread the disease by biting an infected person and passing the virus to others. Being vaccinated would decrease the chances of turning the mosquito into a carrier.

“Those who have received the vaccine, if they get infected, they are less likely to transmit to others. So in a way, it offers some protection to (other people) as well,” said Prof Dr Rafdzah Zaki, an epidemiologist at the Department of Social and Preventive Medicine, Universiti Malaya.

All the experts said taking the vaccine should be made part of Malaysia’s effort to reduce dengue cases and deaths, but added it should not be the only method to achieve its aims.  

 

Experts acknowledge the seriousness of vaccine hesitancy attitudes in Malaysia, caused in no small part by the Dengvaxia scandal in the Philippines where 19 children who had received the Sanofi Pasteur vaccine died from dengue-related complications. 

Subsequent investigations found the vaccine, which acted like an infection, made subsequent dengue infection worse among those who have never had dengue before. Second dengue infections tended to be more severe. 

Epidemiologist Prof (retired) Datuk Dr Awang Bulgiba Awang Mahmud described this phenomenon as antibody-dependent enhancement, calling dengue a complicated disease. 

“Dengvaxia failed in the Philippines because there was a rush to mass vaccinate without taking into account if people had had a previous dengue infection or not (seropositive vs seronegative). It could have been avoided if a pilot project had been run to determine first (whether participants have had dengue before),” he said.

Dr Awang Bulgiba, who is also an International Science Council Fellow, added that Malaysia should establish the Takeda vaccine’s effectiveness against all four types of the dengue virus and safety for all recipients regardless of whether they have had dengue previously, before embarking on a mass vaccination campaign. WHO has recommended that Qdenga be included in national immunisation programmes.

Currently, the Takeda dengue vaccine is available privately at select clinics and medical centres.

Dr Zulkifli said misinformation surrounding COVID-19 vaccines, especially those using the new mRNA technology, has made people suspicious of vaccines, taking pains to emphasise that the Takeda vaccine is different.

“It uses live, attenuated virus, not the mRNA. We know people are afraid of vaccines because we see many (comments) on social media,” he said.

He and other experts advised the public to consult their doctor about the vaccine instead of relying on a social media influencer.  

 

Despite the advice given by experts, overcoming vaccine hesitancy is no easy matter. Many lay persons do not understand how vaccines are made or the long process they go through before receiving approval. The transparency of data, such as reporting of side effects, is often weaponised as “evidence” that vaccines are harmful.

But trying to reach people with dry, medical facts and jargon may, in fact, turn them off.

Universiti Sains Malaysia communications expert Dr R. Kumaran told Bernama the authorities do not have as much credibility in the age of social media as before. Some people may also be experiencing vaccine fatigue.

However, that does not mean they are out of reach.

The linguist, who specialises in health communications among others, said the message should be as positive as possible and focus on the benefits of getting the dengue vaccine.

“You have to take the socio-cultural approach where, if you take the vaccine, what are the benefits you're gonna get at the society level,” he said.

“Talk about the emotions and desires of those people, about how taking the vaccine leads to something better because if we keep saying, ‘Oh you will have fewer symptoms if you get the vaccine’, it’s not something immediately tangible (for the public).”

He said the messaging should also be consistent across all platforms, unlike the COVID-19 vaccination campaign which saw a lot of public messaging at first but was barely seen or heard when it was time to take the booster shots. 

He stressed that public health messengers should be as diverse as possible, coming from all ages, genders, backgrounds, ethnicities and nationalities.

“When you see somebody like yourself there, there is a sort of affinity so I think people listen better,” he said.