It has become clear that we have to learn to live with Covid-19, till an effective vaccine is available, and possibly after that as well. The upside amid this gloom is that the scientific community was never this enthusiastic about developing any other vaccine as it is today for Covid-19. In less than six months, nearly 180 vaccine candidates have been registered and nearly three dozen of these have entered the human trial stage. There are two vaccines in this race from India as well that have entered human clinical trial stage. Six vaccines have entered the phase III of clinical trials to assess their efficacy and two of these — one from University of Oxford in the UK and the other under development by Moderna in the United States — are being considered as front runners. The results from early-stage clinical trials of these vaccines have shown promising outcomes on safety and immunogenicity parameters. They have also generated both antibodies and T-cell responses.
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Vaccine research and development is a meticulous process, where pre-clinical studies in laboratories and on animals are followed by three phases of trials on human beings. The first phase of trial is focused on knowing whether the vaccine material is safe for administration in humans and if it is leading to the immune reactions it intends to (termed immunogenicity). The next two phases of clinical trials focus on safety, immune reaction or immunogenicity, and whether the vaccine content is generating sufficient levels of antibodies to protect the vaccinated individual from the disease — the efficacy.
The key difference between phase II and phase III trials is that while the former is conducted on a smaller number of healthy people, the latter involves a larger group of people belonging to different age brackets. The number of people involved in Phase II trials are a few hundred while in phase III trials it can go up to a few thousand. The phase III trial of one of the candidate vaccine is being planned on 30,000 participants. At every stage, data is reviewed by an independent data safety monitoring board. The data and information from the each stage of trial is reviewed by independent data safety & monitoring board (DSMB) or an equivalent mechanism. The next stage of trials is started only after it meets certain predefined criteria such as safety and efficacy.
At every stage, there is a close watch. Very few vaccine candidates reach the next stage. Only one in every five to 10 vaccine candidates reach the next stage. The average time taken in vaccine development is around 10 years. It took India nearly 3 decades to develop the first indigenous rotavirus vaccine since the identification of the virus strain. Scientists across the world are still working to find an effective vaccine against HIV/AIDS since the virus was first identified around 4 decades ago.
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But Covid needs speed
What is happening in the case of Covid-19 vaccine development is indeed an accelerated attempt. The scientific community has stepped up to the challenge. The vaccine candidates were identified within a few weeks of the full genome of the virus being made public on 11 January 2020. A number of vaccines are being attempted in ways that have never been deployed before. The scientists can be compared to the 15th century sea explorers who went on a voyage to find the ‘new world’. All the routes were tried at and whoever was lucky found a new place. Vasco da Gama arrived in Goa and Christopher Columbus ended up on the shores of what we call today the US, thinking he had reached India. The scientific community is following a similar approach to find a vaccine for Covid-19. All of us hope that more than one of them succeeds.
Completion of all phases of trials, even an accelerated one, would take at least 6-9 months. The successful outcomes in trials are followed by approval of the licensing authorities in the countries where the vaccine will be used. The licensing authorities scrutinise and examine all the relevant data, before any vaccine is allowed to be marketed. Understandably, the processes take another 6-8 months. Although the processes have been accelerated in the case of Covid-19 vaccines, there is a limit to the development speed because licensing would mean mass-scale vaccination of millions of people, and hence, would require minimising the probability of error, which should be kept close to zero.
It is because of these limitations and requirements that many experts say the earliest a vaccine could be available for public use would be towards the mid of 2021. Furthermore, even if a safe and effective vaccine is licensed, the manufacturing of sufficient doses for administration to 800 crore people would require global collaboration among manufactures, and of course a lot of time. The governments have already started planning as to how the vaccine will be used. It is likely that the vaccine will not be available for everyone initially, and will only be offered to high-risk individuals such as health workers, elderly and people with co-morbidities.
A vaccine for public use and open access to wider public at affordable prices is unlikely to be available before 2023 or even later. So, it is important that while we hope for an early development, we continue to take preventive measures such as wearing face masks in public, regularly washing our hands with soap (or sanitise with alcohol-based disinfectant), following cough etiquettes and maintaining social distancing, which would continue to be key weapons in our fight against the Covid-19 disease.
The people of the country where the vaccine is developed are likely to have higher access. However, as a matter of solidarity, it has to be shared with other countries as well. This is a big reason why India needs to step up its efforts to develop the vaccine indigenously. Some of the efforts by Indian vaccine manufactures are promising and commendable.
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Need to embrace vaccines
Vaccine research, development and licensing is a meticulous process in India and all countries of the world. Vaccines are amongst the safest and effective public health interventions. Yet, unfounded doubts are raised against vaccines and these are not sufficiently used. In 2015-16, of every 10 children in India, around 4 did not receive licensed, available and safe vaccines offered completely free under government’s Universal Immunisation Program. It is time we start putting our faith in existing and licensed vaccines, which remain grossly under-utilised. The use of vaccines among adults and other high-risk population also needs to be encouraged.
The Covid-19 vaccine will go through rigorous safety processes. This underscores that all existing vaccines, including those which were not developed with similar urgency had been licensed and made available after thorough review when found both safe and efficacious. As we wait for a Covid-19 vaccine so desperately, we also need to repose our faith in all licensed vaccines and encourage their use for a healthier society.
Chandrakant Lahariya is a New Delhi based epidemiologist, vaccine expert and public health specialist. Views are personal.