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Vaccine countdown

By Bill Emmott, co-director, GCPPP, June 19th 2021

Compared with one week ago, Brazil’s daily rate of vaccinations has risen from 859,000 to 1.29 million and India’s from 2.95 million to 3.53 million; China’s has stabilised at nearly 19 million daily; the global daily rate has risen to 37 million. Africa however has slowed badly, from more than 800,000 daily to just 307,000 on Our World in Data’s latest reckoning. Overall, in one week 33 days have been cut from the world ex-China’s countdown to herd immunity or 29 from the world including China.

Our clock is intended to provide an illustrative framework for thinking about what needs to be done to get the world speedily to achieve herd immunity. It is not a prediction. Nor does it imply any view about when the pandemic might be considered “over”, given uncertainty about the possible need for boosters, or annual COVID vaccines. But it treats global herd immunity as a significant milestone on the journey, one that could be reachable surprisingly quickly — if the right actions are taken.

The basic arithmetic is simple. World population is an estimated 7.9 billion. Of those, 74% are thought to be over the age of 15, amounting to 5.85 billion adults. Thus roughly 11.7 billion doses in all will be required to fully vaccinate that number of people.

Scientists differ about what proportion of those adults needs to be vaccinated to achieve the level known as “herd immunity” at which point the virus will lack sufficient hosts in order to replicate and spread. We have therefore taken the higher end of the range under debate, namely 80%, which is also prudent given uncertainty about the efficacy of some vaccines against the virus. This gives us 4.68 billion adults, or 9.36 billion vaccine doses. If single dose vaccines become more prevalent, then the process would of course be speeded up.

As of June 19th, according to Our World In Data a total of 2.62 billion vaccine doses had been administered, worldwide. Subtracting that from 9.36 billion gives us the target required of a further 6.74 billion. Our World In Data reports that the latest seven-day rolling average of daily vaccinations worldwide is 37 million. If that daily rate could only be maintained, the world would achieve herd immunity of 80% in just 182 days (as of June 19th: the clock display shows how this has reduced since then).

This is far sooner than most people realise. Only about six months from now. But some significant policy interventions will be required if it is to be achieved or, even better, improved upon. Moreover, it comes with one big caveat, albeit one that is itself instructive. This is that if we look behind that now impressive daily figure, we see that almost half of those vaccinations are currently taking place in China.

This represents a dramatic acceleration in China’s vaccination programme since the beginning of April, when just 5 million doses a day were being administered, against 16-20 million now. Since China’s 1.4 billion population represents nearly a fifth of humanity, achieving herd immunity in that country will be a big step for the world too. But for our framework to be fully illustrative, we need to also adjust for China’s currently exceptional performance.

Alongside the basic arithmetic it is therefore worth considering another set of sums: for the world adult population minus China. Subtracting China’s 1.4 billion from the global 7.9 billion gets us to 6.5 billion; 74% of that number gives us 4.8 billion adults, making the herd immunity level of 80% equivalent to 3.85 billion. That requires 7.7 billion doses. So far, China has reported just on 1 billion vaccinations, meaning that the world ex-China total for doses administered so far amounts to 1.62 billion, which means there are 6.08 billion to go.

Dividing that by the 18 million being administered daily gives us a countdown time of 337 days, at what we might call the current “world ex-China” daily rate. That is just over 11 months, which is more than a month fewer than just one week ago thanks to increases in vaccination rates. Compared with one week ago, Brazil’s daily rate of vaccinations has risen from 859,000 to 1.29 million and India’s from 2.95 million to 3.53 million. Africa however has slowed badly, from more than 800,000 daily to just 307,000 on Our World in Data’s latest reckoning; in total, Africa has vaccinated just 42.73 million people out of a total population of 1.3 billion.

There’s the world’s task in a nutshell: to narrow the gap between the present 337 days for “world ex-China” and the 182 days for the world including China, the difference between January and July 2022. Of course, poorer and more rural countries will find it harder than richer, more urbanised ones to vaccinate rapidly. But that is not what most of the currently unvaccinated world looks like. China has increased its vaccination pace almost fourfold in less than two months, so doing so cannot be impossible, especially for other middle-income countries that are presently lagging but have comparable resources and health systems.

Vaccine supply is one important constraint on that replication and acceleration, but it should be noted that since China is one of the major manufacturing centres of COVID-19 vaccines, once it achieves or nears herd immunity, a large supply of Chinese vaccines is going to come available. Those vaccines are believed to have lower efficacy than the western vaccines, which adds to the case for setting a high target threshold for herd immunity, both in China and elsewhere.

The supply of all approved vaccines — Western, Chinese, Russian and Indian — is increasing every month. Our monthly report on global vaccine production  showed a doubling to 822 million doses in May, and in fact in the first week of June a further 299 million were produced.

The final implication of this vaccine countdown calculation is that in coming months, the biggest constraint on the journey to global herd immunity is likely to become the financing of vaccine acquisition for poorer countries and of additions to the public health and public administration resources available to carry out vaccinations. That is where international policy interventions, by all countries that can afford it and by major foundations, are going to be needed. An excellent and much-cited paper, “A Proposal to End the Pandemic”, by Ruchir Agarwal and Gita Gopinath of the International Monetary Fund, has put a total cost of these interventions and of boosting vaccine manufacturing capacity at $50 billion, some of which may already have been pledged. This is a small sum when compared with the economic gains in prospect for all countries, rich and poor. Absent those interventions, the world will not achieve herd immunity as rapidly as it could.

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