In vaccine race last lap, the key steps for India
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Linked to the government plan of supply from multiple sources is the need for a concise recipient prioritisation policy
- Evaluation of candidate vaccines for COVID-19 should be done on technical parameters and programmatic suitability.
- An ideal vaccine would provide all of these — immunity that is of a high degree (90% + protective especially against severe illness), broad scale (against different variants) and durable (at least five years if not lifelong); a vaccine that is safe (little or no side-effects and definitely no serious adverse effects); a vaccine that is cheap (similar to current childhood vaccines); a vaccine that is programmatically suitable (single dose, can be kept at room temperature or at worst needs simple refrigeration between 2°C and 4°C, needle-free delivery), and a vaccine that is available in multidose vials, has long shelf life and is amenable to rapid production.
- Obviously, a vaccine having all these desirable characteristics is a pipe dream and most vaccines would fare well in some and not so well in other parameters, making it difficult to choose between them.
- Also, at this stage, we are only looking at a one-time use of this vaccine to stop the novel corona virus pandemic as the requirement for a regular vaccination (as for influenza) would be somewhat different.
A difficult vaccine to develop
- Historically, we have faced difficulties in the development of corona virus vaccines.
- Although there were some attempts at development of vaccines against Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS), there are no licensed vaccines for any corona virus yet.
- Previous corona virus vaccines were found to be immunogenic (generate antibodies as in phase II) but did not effectively prevent acquisition of disease (phase III) fuelling a concern that vaccination may not induce long-lived immunity, and re-infection may be possible.
- There are also safety concerns due to immunological consequences of the vaccine as these vaccines use newer techniques with which we do not have long term or large population experience.
- About the safety of vaccines, there are always possibilities of rare (one in million) or delayed (by months or years) serious adverse events which will come to light only after mass vaccination has started; this requires a good post-licensure surveillance system to be in place.
Most could be in two doses
- The COVID-19 vaccine candidates by Moderna and Pfizer have already released early information of high effectiveness (90%+).
- Pfizer’s two-dose shots need to be stored at minus 70°C something which is beyond India’s current vaccine storage infrastructure.
- Moderna’s vaccine is more thermostable and has a requirement similar to what we used for oral polio vaccines.
Ranking by risk category
- We already know that government has planned for vaccine supply from different sources.
- The World Health Organization has issued guidelines for prioritisation for vaccine recipients.
- Need to rank population sub-groups by risk category (risk of infection or adverse outcome or economic impact), and by programmatic ease of vaccination — based on their captivity (health-care workers, organised sector, workplace, schools), and access to existing channels of vaccination (pregnant women and children).
- Start with where these two criteria intersect — health-care workers followed by policemen.
- The third rule is using multiple channels to immunise the population.
- Other important considerations would be of equity and cost. Obviously, military and paramilitary staff will be dealt with as a special case due to their high captivity and national security considerations.
- The first product off the block may not be suitable in terms of cost and cold storage, but if the priority is health-care workers, then we could go ahead and buy some (how much is a trade- off) vaccines for this group if it is above 75% effective, as it is possible to immunise health-care workers keeping cold storage requirements at their own facility, including in private sector or district hospitals.
- The same infrastructure can also be used to vaccinate the police force.
Models of social mobilisation
- Problems will arise as we move towards vaccinating the general population, even high-risk groups (the elderly and those with co-morbidity) in the general population.
- It might be easier to vaccinate the institutionalised elderly as compared to community-dwelling ones.
- However, the greatest challenge would be to immunise the poorest and the most vulnerable (slums/migrants/refugees/people with disabilities).
- Because of access issues, this must be by an outreach or camp approach (booths along with web-enabled appointments facilitated by civil society); a programmatically suitable vaccine will have to be prioritised for them.
- It is expected that the pandemic would start receding once we protect about 60% of the population (in terms of coverage x effectiveness).
Dealing with ‘pay and get’
- One major challenge would be that many people would be willing to pay for the vaccine and ask for expedited access.
- Obviously, till we cover a bulk of phase 1 beneficiaries, the government should not concern itself with other groups.
- However, it can and should allow the vaccine to be available in the private sector at a market-driven price for such people.
- It will be ethical as well as cost-saving for the government, if it does not divert vaccines from the government-driven programme.
- Many countries have already published their prioritisation policy whereas in India, it is only based on what we hear from the media — that health-care workers have been prioritised and details are not available in the public domain.