BENGALURU: As the world is in a race for an ideal vaccine candidate to protect people against coronavirus, experts say we can expect a vaccine only by early 2021. Given the current speed at which clinical trials are going on, the first generation of vaccines may not be effective on everyone.
There is a lot to be figured out by the government on the logistics of distribution of vaccines to ensure it reaches all, said Dr Anant Bhan, Researcher, Global Health, Bioethics, and Health Policy, during an interview with The New Indian Express.
Excerpts.
Which Covid vaccine candidates are leading the race?
There is Bharat Biotech's Covaxin which recently initiated Phase-3 trials. AstraZeneca's and Serum Institute's Covishield is in Phase-2/3. Zydus Cadilla's ZyCoV-D is in Phase-2. Dr Reddy's and Russia Direct Investment Fund received the DCGI approval to conduct an adaptive phase 2/3 clinical trials for Sputnik V vaccine in the country. Serum Institute is also partnering with Novavax for NVX-COV2373, for which phase 2/3 trials are supposed to start soon in India. Trials are also being done on the existing ones, like the anti-tuberculosis vaccine, BCG, in India and abroad.
When can we expect any of these vaccines to be ready for India?
I don't expect any candidate to be ready before early next year. For instance, Astra- Zeneca's ongoing trials in India with 1,600 participants is set to take seven months for completion. The regulator may also use the data from foreign vaccine trials and implement emergency use of the vaccine, given the special pandemic situation. The data safety and monitoring board can look at interim results and recommend either to stop the trials if there is a risk or give the go-ahead if there is strong evidence of a vaccine's efficacy. In the latter scenario, the vaccine could be made available early based on the regulator's approval.
It takes 10-15 years to bring a vaccine to the market, but now all companies are trying to get a vaccine out in a short span. The UK Vaccine Task Force has said that the first generation shots will be imperfect and may not work on everyone.
First-generation shots being imperfect and not being effective on everyone/optimally effective is quite likely, due to the rapid speed at which trials are taking place. There is not enough time being given to understand the safety and efficacy, especially long-term protection. The later generation of vaccines could have more efficacy as more time would be available for development. Also, developers can understand what works and what does not, and have better knowledge of virus immunology. Also, clinical trials are done in controlled and ideal settings. On the field, however, the actual performance may be different. Another factor is the cost. Lower and middle-income countries may opt for specific vaccines if the cost is high or be part of mechanisms such as the Covax facility, a global risksharing mechanism for pooled procurement and equitable distribution of eventual vaccines.
Who can rceive the vaccine first?
Countries must use clear frameworks developed and used in past pandemics to decide on whom to prioritise. The decision can be made based on those who are most at risk, such as healthcare workers, elderly and those with comorbidities. It can be made based on the professions most critical in response to the pandemic, such as healthcare workers, sanitation workers, civil defence, security forces, etc. It can be made based on age and vulnerability. It could be made based on political factors as well. However, the process must be made transparent in India, with the rationale in deciding a vaccine or a particular target group made public.
What kind of manufacturing facility will we need to scale up production?
Several companies in the country already supply vaccines globally, have large capacities and plan to upgrade their facilities to meet the demand. The production also depends on the collaboration between those who developed the vaccine, such as Oxford University, and vaccine manufacturers, such as Serum Institute of India, and whether other companies can be involved in production. The government can also step in and mandate production under special provisions.
What logistics are needed to ensure effective distribution of vaccines?
We need to figure out the distribution chain, cold-chain facilities and at what level will they be delivered, such as local PHCs, district hospitals or even door-to-door, etc.. The government must also decide on who should administer it, how to ensure continuity of supply, how many syringes will be needed, who should be prioritised in receiving the vaccine and how we will track those who have been vaccinated. Some people may not agree to get a dose.
What is likely to happen in a person's body once the vaccine is administered?
An effective vaccine would produce an immunogenic response, that is antibodies to prevent the onset of Covid infection and the body must be able to fight off the virus. There should also be long-term memory in the immunity. Say, 10 years down the line, the immune system must be able to create antibodies if the virus enters. We also need to look at how long the antibodies or the immune memory lasts, and if booster doses are needed.