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Can vaccines with emergency use approval be used at the population level?

Home truths: Vaccines tested and manufactured in India would take some more time to reach the stage where data are available to support emergency use approval.   | Photo Credit: ktsimage

Pfizer’s mRNA vaccine has been approved for emergency use by the UK, Bahrain, Canada, Mexico and the U.S. The company has also applied for emergency use approval (EUA) in India. The emergency use approval has been based on safety and efficacy data from limited follow-up. Vaccines tested and manufactured in India would take a little longer to reach the stage where data are available to support emergency use approval.

Meanwhile, the Indian government has spelt out four high-risk groups — healthcare workers, frontline workers, those over 50 years of age and those aged below 50 years but with co-morbidities — would get the vaccine on priority. Most countries too identified the priority groups that would receive the vaccine first.

Pfizer has already indicated that it plans to file for full FDA approval in April next year; it was granted an EUA by the U.S. FDA on December 11. Moderna and AstraZeneca too are likely to apply for full approval sometime next year once the trial is complete; vaccines from these two manufacturers are yet to be approved for emergency use by any country. In all likelihood, vaccines including the Indian ones granted emergency use approval in the next couple of months are likely to have safety and efficacy data to seek full approval at least by the end of next year.

Eligibility questions

With the focus on breaking the transmission chain by vaccinating a “critical mass of people”, the question is whether people who do not belong to the priority groups will be eligible to get the vaccine even before a full approval is granted. “The special authorisation for use of vaccines at the population level based on early/interim data should be done with adequate oversight and by paying adequate attention to the need for collecting data on safety, efficacy through good quality pharmacovigilance,” says Dr. Anant Bhan, a researcher in global health and bioethics in an email. He feels that it is not important for COVID-19 vaccines usage permission to be restricted only to high-risk populations if there is close oversight.

Virologist Dr. Shahid Jameel, Director of the Trivedi School of Biosciences at Ashoka University too shares the same idea that vaccines approved for emergency use should be available to all. “My understanding is that EUA is given during public health emergencies. That emergency is the same for everyone,” he says in an email. “What is the point in developing vaccines while the pandemic is on and then not deploying them to control the pandemic? Seems silly.”

Safety data

Dr. Jameel then goes on to stress that safety data from limited follow-up would be sufficient even for universal vaccination. “When is safety testing enough? Data for many prior vaccines show that most adverse events take place within six weeks of immunisation. That is the logic for two months (US FDA) or 70 days (Europe Medicines Agency) waiting before EUA is granted,” Dr. Jameel says.

Evidence-based usage

However, Dr. Giridhara Babu, epidemiologist with the Public Health Foundation of India, Bengaluru does not agree with universal vaccination based on emergency use approval. “Full approval is needed before beginning universal vaccination. Mass vaccination with any vaccine for which only partial data is available is unethical,” Dr. Babu says in an email. “Evidence-based implementation is essential for mass vaccination. Therefore, vaccines that have only emergency use approval cannot be considered for mass vaccination.”

Also, the DCGI has to clarify under what rule will it grant permissions for widespread usage since emergency use approval is not as such mentioned in Indian drugs/vaccines related laws and rules, says Dr. Bhan.

But no country including India has plans for widespread vaccination based on emergency use approval. Also, the high-risk groups in India earmarked for vaccination on a priority basis once vaccines get emergency use approval works out to 300 million people. It might very well take a year to vaccinate the priority groups.

In mid-November, Serum had manufactured 40 million doses and was to soon begin making Novavax vaccine. Clinical trials of other vaccines are currently under way in India. Vaccines such as the ones tested by Pfizer and Moderna will be expensive when available in India and might not be used by the government to vaccinate high-risk groups.

Pfizer had however told the media that it would not make the vaccine available in the private market during the pandemic phase. The question really is whether such vaccines with emergency use approval should be available in the open market for anyone to purchase and get vaccinated, says Dr. Jameel.

But after two healthcare workers vaccinated with Pfizer’s mRNA vaccine in the UK responded adversely, the government warned that people with allergy should not be given the vaccine. This reveals that vaccines that have been approved for emergency use need to be continually monitored and appropriate actions be initiated when adverse effects arise, says Dr. Babu. “It is important that we have strong systems that quickly pick up such risk factors and a regulatory system which makes decisions promptly based on these,” says Dr. Bhan.


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Printable version | Jun 22, 2021 8:46:50 PM | https://www.thehindu.com/sci-tech/science/can-vaccines-with-eua-be-used-at-the-population-level/article33315448.ece

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