MANILA, Philippines — In about a month’s time, Filipinos may start taking part in the biggest global effort to find a vaccine to end “one of the most devastating epidemics” humanity has had to face.
The clinical trials for a COVID-19 vaccine in the Philippines are going to be different from those it had hosted in the past, given the high stakes after the new coronavirus had already killed more than 1.3 million people in 191 countries nearly a year since the outbreak in China.
More than a hundred vaccines against SARS-CoV-2, the virus that causes the severe respiratory disease, are being developed worldwide and undergoing various stages of clinical trials. Such trials ensure that a vaccine is both safe and effective for people.
A candidate vaccine first undergoes a preclinical trial in which it is tested on mice and monkeys to see if it produces the desired immune response.
After that stage, the vaccine goes on to three phases of human trials.
Phase 1 involves a small number of people, typically between 10 to 100 to test the vaccine’s safety.
A much larger group of at least 100 to 1,000 people are enrolled in Phase 2 to determine its effectiveness and the right dosage.
For Phase 3, at least 1,000 are enrolled to confirm the vaccine’s safety and efficacy.
Leading candidates
Barely 11 months since the virus emerged from a wet market in Wuhan, China, two candidate vaccines have been found to be 95-percent effective.
These vaccines were developed by Pfizer/BioNTech and Moderna and the US National Institutes of Health, which did not hold clinical trials in the Philippines.
The country, however, will take part in an international Solidarity Trial on Vaccines led by the World Health Organization (WHO).
Separately, at least five other pharmaceutical groups have either expressed their intention or are trying to secure clearance to hold their Phase 3 trials in the country. These independent trials are for vaccines developed by China’s Sinovac and Clover Biopharmaceuticals, Russia’s Gamaleya Research Institute, Johnson&Johnson of the United States and the United Kingdom’s AstraZeneca.
Sinovac is ahead of the others as it now awaits approval to begin its Phase 3 trial from the ethics board of the Department of Health. It would need at least 1,000 volunteers or participants.
Participant pool
Science Secretary Fortunato dela Peña said the WHO Solidarity Trial, which could involve four candidate vaccines, may begin in December, with its pilot in the Americas expected to start this month.
The WHO had asked the Philippine government to increase its participant pool from 2,000 to 4,000.
To determine a vaccine’s effectiveness, a trial participant is given the vaccine or a placebo. According to Dr. Lulu Bravo, executive director of the Philippine Foundation for Vaccination, neither the participant nor the health worker knows what the volunteer was injected with.
Only the members of the data safety and monitoring board overseeing the trials know, said Bravo, a pediatric infectious disease expert who has participated in various clinical trials over the last three decades.
Once inoculated, trial participants can go about their usual activities. They will be constantly checked by researchers and must report to trial investigators if anything feels amiss.
Don’t be complacent
The participants must not be complacent and should continue to observe the minimum health measures to avoid contracting the virus like everyone else, Bravo said.
If an “adverse health event” is recorded in any of the trial participants, the data and safety and monitoring board has the power to halt the study or the trial sponsor can implement a pause.
Volunteers, who are asked to sign an informed consent form, are not paid and may even receive a small “allowance.” The company concerned must cover the medical expenses incurred by the volunteer in case of an adverse event related to the candidate vaccine.
According to Sanofi Pasteur Philippines general manager Dr. Jean-Antoine Zinsou, a temporary pause on a candidate’s vaccine trial should not cause alarm as this only shows that the trial monitoring is working.
“This is a very good signal when you have companies interrupting a study, it means people are not rushing, they are doing things properly,” he said.
“We need to admit the fact that whatever the quality of a Phase 3 study, it will never ever cover all the specificity in the world and therefore there will be some adjustment of the indication along the way,” he said. “What’s important is whenever you have an adverse event, it is properly managed.”
Criteria for choosing
One of the criteria for choosing the community where the trial may be conducted is its high rate of virus transmission.
Dr. Beaver Tamesis, head of the Pharmaceutical and Healthcare Association of the Philippines, said this will help “demonstrate quickly that your vaccine actually works.”
“If there’s no actual community transmission or spread of the virus in a rapid manner, in all likelihood you have to wait weeks, months, forever to get an actual statistical result,” said Tamesis, who also heads the American pharmaceutical company Merck.
While vaccine development advances, scientists continue their studies on the origins of the virus.
“We are trying our best to ensure the best science in the face of one of the most devastating epidemics we’ve had to face together as a planet,” Mike Ryan, executive director of the WHO’s health emergencies program, said last month.
“We want to get the best, the right answers so we can take the best possible risk management measures into the future,” he said.
Health officials said they were constantly monitoring the situation in various localities where the trials may be held, especially the country’s major population hubs—Metro Manila, Cebu and Davao.
The country had 415,852 infections with the addition of 1,791 cases on Saturday.
Tarlac reported the most number of new cases, 211, followed by Davao City (115), Laguna (74), Cavite (69) and Negros Occidental (65).
Another 328 patients have recovered from COVID-19, bringing the total number of COVID-19 survivors to 375,548. The death toll, however, rose to 8,080 after 55 patients died.
The recoveries and deaths left the country with 33,224 active cases, of which 84.5 percent are mild, 8.7 percent asymptomatic, 0.2 percent moderate, 2.3 percent severe and 4.3 percent critical.
Bravo is urging health authorities to carefully screen volunteers to prevent antivaccine groups from undermining or casting doubts on the clinical trials by spreading unfounded allegations against any of the candidate vaccines.
Zinsou said that education and information campaigns about vaccines and the trials should be ramped up as soon as possible to prevent misinformation and disinformation, as well as hesitancy to get vaccinated.
“It’s very important that we do not stand still waiting for the vaccine to arrive. We have a lot of work to do to get prepared,” he said.
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