On 16 January 2021, the Union government's vaccination program started with eligibility limited to front-line workers. On 1 March 2021, eligibility was extended to a) those above the age of 60, and b) for those above the age of 45 with co-morbidities. This was further opened up to everyone above the age of 45 from 1 April 2021. On 20 April 2021, the union government announced that from 1 May 2021 the minimum age of a person that is able to obtain a vaccine will go down from 45 to 18.

It is useful to juxtapose this recent expansion, from age 45+ to age 18+, against the structure of the population, and envision the magnitudes involved.

The last available census in India was in 2011. It is likely that the age structure of the Indian population has changed since then. We use the Consumer Pyramids household survey data of the Centre for Monitoring the Indian Economy to get the following age structure, based on an estimated population of 1.4 billion for late 2020.

Age group Population
0-17 years 344 million
18-44 622
45-59 321
60+ 125

By 26 April 2021, 142 million vaccine doses had gone out. Of these 119.6 million persons have got one dose, and 22.5 million have got both doses. However, of the 142 million doses, about 11.2 million doses have been to persons below age 40. In the eligible population of 45+, a little less than five per cent have received both the doses, while a little less than 27 per cent have received the first dose. There is considerable room to go, in completing the work of vaccinating persons above age 45.

The Union government was pushing out approximately 2.3 million doses in the eligible population per day. This translates to 5.1 doses per 1000 eligible persons per day. This reflects a combination of distribution capabilities, vaccine hesitancy and supply constraints.

Opening up the vaccination to those above age 18 has meant that the size of the eligible population has gone up from 446 million to 1.06 billion. If we subtract those who have already been vaccinated, we end up with an eligible population of 926 million. The eligible population has thus roughly doubled. To preserve the erstwhile run rate per unit eligible population, the number of doses per day would also need to roughly double. In late April, there were anecdotal reports of shortages, where eligible persons were turned away at vaccination centers. Looking forward, this may become a bigger problem with the expansion of eligibility.

If all else is held intact, then, there will be a larger mismatch between demand and the ability of the Union-government led system to push out doses. There are two pathways to not hold all else intact. On one hand, there is the need to shift from a Union government-led system to something that is a self-organising system, with energy from many persons, and thereby speed up the availability of vaccines. On the other hand, there is a need to rethink vaccination protocols. For example, if a person has antibodies, perhaps one dose suffices.