SHOT IN THE DARK

It took less than a year to come up with what would normally take a decade to achieve, but the endeavour to formulate a coronavirus vaccine was madepossible because of the publication of the entire genetic code of the coronavirus, which first emerged in the city of Wuhan.

Chinese scientists early last year allowed researchers to hit the ground running without needing samples. It marked the start of the arduous race for an effective formula, with results coming in record time.

More than a year after Thailand first declared war on Covid-19, which now infected morethan 12,000 people, the country finally saw the light at the end of the tunnel when the government recently ordered 2 million doses of vaccines from the Beijing-based biopharmaceutical company Sinovac, deliverable from next month until April, despite growing concerns about its efficacy rate dropping from 78% to 50.4% in Brazil.

This is part of this year’s plan to vaccinate at least half of the country’s population. The government has also pre-ordered 26 million doses from AstraZeneca and Oxford University for rollout from May to June, followed by an additional 35 million doses later this year. The final phase will see more vaccines being made available to the general public.

Basically, vaccines work by teaching human bodies to recognise foreign germs and attack them, but they differ in production. The World Health Organization (WHO) reported that there are now at least 64 Covid vaccines in clinical trials on humans. However, some of them are now under scrutiny, following several reports of deaths resulting from the rushed authorisation of vaccines that haven’t been thoroughly tested.

With vaccines expected to hit Thailand’s shores next month, a large number of consumers are still frowning upon the efficacy and raising concerns over side effects. In light of this healthcare debate, Life sat down to talk with medical experts to discuss various aspects people need to be aware of before making an informed decision about vaccination.

CURRENT VACCINE PLATFORMS

Speaking during a forum at King Chulalongkorn Memorial Hospital earlier this month, Dr Kiat Ruxrungtham, director of Chulalongkorn University’s vaccine development programme, said the third phase of clinical trials has now seen five vaccine types.

“One of them is a viral vector vaccine. It uses an innocuous virus that causes the common cold in humans or chimpanzees to carry a tiny part of the coronavirus’s genetic code [into human bodies],” he said.

An example is the vaccine developed by AstraZeneca and Oxford University. It is around 70% effective and easy to transport and distribute because it can be stored in a normal fridge.

Kiat drew attention to the new technology of messenger RNA (mRNA) that uses a small fragment of the coronavirus’s genetic code. Pfizer-BioNTech and Moderna are adopting this approach — the first ever to be approved for use in humans. They are found to be over 90% effective, but must be kept in freezers.

“If we know the genetic sequence of the virus, we can replicate it to make vaccines without using the real one,” he said.

Meanwhile, some vaccine manufacturers, including China and India, still use the traditional method of the inactivated vaccine. Kiat said it is made by growing and killing viruses on a large scale, using chemicals, heat or radiation. Front-runners include China’s Sinovac and Sinopharm.

The rest are DNA and protein-based vaccines. He said prototypes in Thailand have seen these five techniques, including the Chula-Cov19 mRNA vaccine.

GUIDELINES FOR CONSUMERS

Patcharaporn Boonyos, medical scientist in virology at the Thailand-Japan Research Collaboration Centre on Emerging and Re-emerging Infections (RCC-ERI), a collaboration between Osaka University and the Ministry of Public Health, said people should take into account three factors — allergens, need and physical condition — before they decide to receive vaccination.

She said those who are allergic to certain types of food and drugs should consider inoculation carefully because each vaccine, though the same type, can cause allergies. For example, Pfizer and Moderna use different ingredients in lipid nanoparticles that envelope the virus’s genetic code.

“If we are allergic to some ingredients [in m RNA vaccines], use other vaccine platforms. You can’t consider only their effectiveness,” Dr Patcharaporn explained.

In addition, she said people should assess the level of need prior to vaccination — are youa frontline medical staff member at risk? There is a misunderstanding that vaccines can prevent coronavirus infection when in fact they simply reduce its severity. For example, those who get vaccinated might develop a cough rather than need hospital care or die.

“Also, vaccines are still not working in asymptomatic patients, who make up the majority of [undetected] cases. Clinical trials show vaccines can tackle severe infections, not asymptomatic and mild cases. People can be reinfected and spread the disease [unknowingly because they think they have been vaccinated],” she said.

She stressed that they should still wear face masks and observe other preventive measures because “they are the best way”.

On physical condition, she encouraged pregnant women, new mothers and children to avoid vaccination for now because vaccines have still not been tested on these groups.

VACCINE EFFECTIVENESS

Patcharaporn said nobody knows how long vaccines can remain effective because the work normally takes 10 years. Scientists spend two years assessing safety and monitor it every year onwards because viruses continue to mutate, thereby reducing vaccine effectiveness.

“Sars-CoV-2 can change and spread very fast,” she said. “The number of infections has jumped from over 5,000 to 10,000 this month, but the actual figure could be far higher because of [undetected] asymptomatic patients around us. It is worrying because the virus will be already ahead when we roll out each each vaccine. Scientists have to start the first phase [of clinical trials] again. Having many vaccine platform scan be helpful when any of them does not work.”

She said, moreover, people should receive the total number of doses within a period stipulated by each vaccine developer. For example, those who get Pfizer’s vaccines must get two doses, three weeks apart, to achieve its full efficacy.

When asked about the possibility of using different vaccines, she said they should be the same, otherwise it will affect how it boosts immunity. “Use the same one. Don’t combine Pfizer with Moderna or mRNA with an inactivated vaccine,” she said.

Patcharaporn added that side effects include pain, rash, headache, fever and vomit, but they will last only two to three days. Nevertheless, people should watch out for adverse effects.

“People should monitor whether they have more respiratory illnesses or antibody-dependence enhancement [a condition in which antibodies increase the ability of the virus to enter cells and cause a worsening of disease],” she said.

FOLLOW-UP FOR SAFETY

Dr Lorenz Von Seidlein, a vaccine expert at the Mahidol Oxford Tropical Medicine Research Unit (MORU), echoed the same view. Nobody knows how long immunity will last because vaccines were just developed last year.

“Of course, you can make projections based on previous vaccine experiences. It is reasonable to assume thatthe vaccine that provides initially93% will still be more effective than50% in the coming years,” he told a forum earlier this month at the Foreign Correspondent’s Club of Thailand.

When asked how to evaluate vaccine safety, he said “it should be an ongoing process” because what usually follows the third phase of clinical trials is pharmacovigilance, or the process of monitoring drug safety.

“National vaccination campaigns should follow up and assess whether people experience adverse events and need boosters, especially in the case of new coronavirus variants,” he said.

NOT A MAGIC BULLET

Meanwhile, Dr Nakorn Premsri, director of the National Vaccine Institute, spoke of the vaccine rush, stressing that getting vaccines first, but in a small amount, will not have any impact on the outbreak situation.

“It needs time and coverage. It is not a race, but a marathon. We must look at it in the long term. A vaccine is not a kind of magic bullet or the only measure. We use it together with our prevention and control measures,” he said.

When asked about migrant workers and expats, he said the government plans to vaccinate prioritised people first, including frontline healthcare workers, elderly citizens, those with congenital diseases and officials in risk areas. The rest will be inoculated respectively when they secure more doses.

“Aiming for 50% [of the population] is just for this year. If we can find more doses, we can vaccinate more people. We will not leave anyone behind. All will be vaccinated according to the prioritised groups,” he said.

The Ministry of Public Health aims to give jabs to 70% of the population to curb the outbreak and create a “herd immunity”.

When asked about private hospitals seeking to import vaccines themselves, he said there is a misunderstanding that anyone can buy them at will. In fact, they have to make purchases from authorised representatives that register their products with the Food and Drug Administration (FDA).

Surachok Tangwiwat, the FDA’s deputy secretary-general, said only AstraZeneca and Sinovac Biotech had applied for their vaccines to be registered in Thailand. The Ministry of Public Health said it has requested further information about the vaccine’s safety from Sinovac, but insisted the government was likely to proceed with its plan.

AS THE GLOBAL RACE TO FIND A COVID-19 VACCINE BEGAN LAST YEAR, WHAT WAS A SPRINT TURNED INTO A MARATHON BUT, ARMED WITH THE VIRUS’ GENETIC CODE, SOME SCIENTISTS HAD A HEAD START − CONSUMER CONFUSION, HOWEVER, STILL REIGNS

STORY:

THANA BOONLERT

VACCINES CAN TACKLE SEVERE INFECTIONS, NOT ASYMPTOMATIC AND MILD CASES. PEOPLE CAN BE REINFECTED AND SPREAD THE DISEASE