Bengaluru/New Delhi: There have been several micro developments in vaccine testing around the world for Covid-19, but none are conclusive enough to get excited about yet, said Adar Poonawalla, chief executive officer of Serum Institute of India (SII), the world’s largest manufacturer of vaccines.
In conversation with ThePrint’s Editor-in-Chief Shekhar Gupta at the digital version of Off The Cuff, Poonawalla said, “For another two or three months, I would urge everyone to completely ignore any vaccine news that comes out.”
The Pune-based company’s CEO explained that all interim reports and media articles coming in are from animal testing or Phase 1 of clinical trials for vaccines. It’s only after Phase 3 trials that efficacy and yields of production can be established.
A vaccine is tested on animals in the pre-clinical stage. During Phase 1, the safety of the vaccine is assessed by administering it to a handful of human subjects. The two subsequent phases increase the number of participants to up to 3,000 to establish if a safe vaccine is also effective.
“A lot of it is fed by Wall Street and other investors who’ve invested in these companies and thus want to create hype and euphoria,” he said. “We need to manage people’s expectations.”
Serum Institute’s collaborations
Adar Poonawalla said SII has partnered multiple companies to develop live attenuated vaccines. These carry a weakened form of the virus, which doesn’t cause sickness but still induces the body to produce antibodies.
With attenuated vaccines, live virus that’s viable but with reduced virulence is administered. The process of “diluting” the virus to make it less virulent is called passaging. Among the vaccines currently available, the rabies, mumps, and rubella vaccines are live attenuated, while bacterial vaccines typically tend to be ‘killed’ or inactivated vaccines.
The vaccine SII is developing with the Austrian company Themis uses the spike protein of the virus. The spike protein is present on the outside of the virus, and is used to bind to human cells. Such molecules, which are present on the outside of a pathogen and directly attack a host’s cells, are called antigens. Antibodies are produced in response to antigens.
Poonawalla said the US-based firm Codagenix’s vaccine, which SII has tied up with to manufacture, is exciting because it is genetically modified to offer broad spectrum protection in such a manner that it could likely provide protection even if the new virus mutates significantly.
“So far, there has not been any significant mutation that we think could pose a problem to the existing vaccines under development, but going forward that could change,” he added, referring to the ability of some viruses, like the influenza virus, to mutate so fast that vaccines rapidly become ineffective.
The Oxford University vaccine (ChAdOx1 nCoV-19) that SII is collaborating on is a safe adenovirus, which is a common-cold causing virus and was derived from chimps, he explained. Phase 1 trials have established safety, and efficacy will now be tested.
The vaccine recently made headlines for failing to protect rhesus monkeys and macaques against Covid but did prevent pneumonia, which occurs when a person is severely infected with Covid and the air sacs in their lungs fill with fluid causing breathing difficulties.
“Today, we have to take a decision whether we will licence vaccines — and I’m sure we will — where if pneumonia and death are prevented, and we can live with some mild symptoms, is that good enough? I don’t think any vaccine can give a 100 per cent protection,” he said.
On what seems to be promising developments on RNA vaccines, notably the one being developed by Moderna, Poonawalla said, “Looking at what works so far is always a good reference point. RNA and DNA vaccines are yet to prove their mettle. The thinking among some epidemiologists is that you might need to be given multiple doses of this vaccine.”
Vaccine trials and safety
Explaining how vaccine trials work, Adar Poonawalla said a vaccine is considered successful only if there is a significant difference in the vaccine arm, i.e., the group that is being administered the vaccine, vs the placebo arm or those who weren’t vaccinated.
Humans can’t be exposed to viruses to test vaccines, due to ethical reasons.
“Whoever makes this vaccine will really have to ensure not just safety and efficacy, but long-term safety and efficacy. Establishing a long-term immune response is going to be a tricky challenge. No one can know now if it’s possible, only time can tell,” he said.
But even when a vaccine comes along, achieving herd immunity doesn’t mean that Covid-19 can be eradicated, he said.
He noted that smallpox is the only disease that has been eradicated through vaccination in humans. Despite billions of dollars having gone into distributing polio and measles vaccines, there are still new cases coming up even today, and the diseases are still not completely eradicated, he said.
“People think that once a vaccine comes along, we can all live happily ever after. There will be a significant improvement, but eradicating a disease is a whole different story,” he said.
Regarding manufacturing and trials, Poonawalla said the Government of India has been very supportive of such work and is helping by doing away with. “A typical (vaccine trial) takes a few hundred or even thousand crores to develop and scale up. The government has been very supportive and has agreed to fund several vaccine trials, including one for (anti-tuberculosis) BCG,” he said.
Poonawalla added he is fairly confident that a functional vaccine will be developed in two years, and that either SII or another manufacturer will definitely produce a global vaccine for Covid-19.
No functional drugs yet
Speaking about the numerous trials for drugs currently under way, the SII chief said there still isn’t enough valid data to show that any of these drugs have demonstrated safety and efficacy to either treat or prevent Covid-19 in a double blinded, randomised controlled study. These are the kind where it can be shown within 3-4 days if a patient being given the drug is recovering as compared to those being given a placebo, he explained.
“Right now, we can make all the hypotheses that we want, but we should not make any recommendations until the trials are fully complete,” said Adar Poonawalla.
Referring specifically to hydroxychloroquine (HCQ) which has been advised by both the Indian and US administrations, and is being administered as a prophylaxis in India for healthcare workers, Poonawalla said, “We are all trying to get easy fixes (to this pandemic). I myself told my chemist to stock some HCQ hoping it might work, even as a preventive (drug), but there isn’t enough data to show that it does. Until all trials are over, we really cannot come to any conclusion regarding the drug.”
Poonawalla also said the SII will manufacture the human papillomavirus (HPV) vaccine in two years, and that he hopes the Government of India will be able to launch its HPV immunisation programme.
“This vaccine may prove to be the single largest protector for women as far as vaccines go,” he said.
HPV is the most common cause of cervical cancer, which is the second largest killer among women.
However, a vaccination initiative in Andhra Pradesh and Gujarat to study the efficacy and plan cost-effective strategies to prevent or control cervical cancer came to a halt in 2010 after seven girls who had received the vaccines reportedly died during the trial.
“The controversy was a little unfounded because the deaths that happened in the trial were due to accidents or by suicide, and were completely unrelated to the vaccine. The vaccine just got a bad name and it got political,” Poonawala said.
Although the deaths were found to be unrelated to the vaccine, a standing committee later concluded that the study violated ethical norms and India’s laws and regulations.
“Pharma companies which had a good vaccine faced flak due to political and other reasons, which were completely unscientific and illogical. No scientific mind feels that HPV vaccines are wrong or bad or dangerous,” Poonawala said.
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