Inequality in access to vaccines has been a constant concern in the largest vaccination campaign in history and, almost six months after it began, the world is effectively divided by wealth. The countries with more than 30% of vaccinated people are rich countries, or relatively rich, while almost no poor country has managed to immunize even 10% of its citizens. GDP distinguishes countries that inoculate at a good pace, many of which are bending their covid-19 curves.
In Spain and the European Union, a third of people have already received at least one dose (33%); twice that of the South American continent (15%), six times more than in Asia (5%) and 20 times more than in Africa (1.5%).
As the graph above shows, the countries of North and Central America were the ones that advanced the fastest at the beginning, pushed mainly by the United States, where they have already vaccinated half the population. But the European Union is the fastest moving forward since April, when vaccine supplies multiplied. The current rate involves administering a dose to 5% of the population each week.
It is not surprising that the continents have vaccinated practically at the rate of their national incomes: with Europe and North America ahead of South America, which in turn is faster than Asia and Africa. The relevant exception is Oceania: neither Australia nor New Zealand have immunized many people, although they are rich countries, probably because they have managed to keep the virus almost suppressed (deaths from covid in this year and a half are there 50 and 300 times less than in Spain, respectively).
The link between vaccines and wealth is even clearer when we look at countries. This is reflected in the following graph, which represents the Gross Domestic Product per inhabitant (horizontal axis) and the level of vaccination so far.
Almost all countries with more than one million inhabitants with 30% of the population already vaccinated (with at least one dose) have a GDP per capita high, above $ 20,000 per capita. The only exceptions are Serbia and Mongolia. And the same thing happens the other way around: there are only four poor countries (less than $ 10,000) that have been able to vaccinate 10% of their population – India, Morocco, Cambodia and El Salvador.
Taking longer to immunize, in countries already marked by strong internal inequalities, has consequences: “we are already seeing in India or Brazil how the collapse of the health system affects tourism and the economy: just as no tourists will go, companies will also they are going to think more about whether to open or move their business there ”, explains Jeffrey Lazarus, epidemiologist and researcher at the Barcelona Institute for Global Health (ISGlobal).
There are a handful of exceptional countries because they have little vaccinated even though they are rich. This is what happens in Australia, New Zealand, Japan or South Korea, which have in common having been successful – or fortunate – in protecting themselves from the virus. A recent study in The Lancet He pointed to them as an example, in the OECD, of the advantages of a strategy of elimination (and not mitigation) of covid-19, in health and also economic terms.
Vaccination and group immunity
The first objective of the vaccine is to protect the vaccinated from becoming ill and dying. We know that this first goal is being successful: according to calculations of the group of Complex Systems of the Polytechnic University of Catalonia, the level of vaccination in Spain at the end of April (25% of people protected; especially older people) should already serve to prevent 80% of deaths from covid-19. But the vaccine will also be effective in preventing infections. A british health report He puts that protection at 70-90% for the second dose of Pfizer. If these figures are confirmed, the question is whether they are enough: is it enough to achieve group immunity?
Reaching it depends on many variables. In essence, we want to keep a reproductive number (R, which estimates transmission speed) below one. And that number depends on various components. On the one hand, how many people are immunized (either because they have had the disease or because they are vaccinated and prevent infection or do not transmit). On the other, from the contact between people, those interactions now reduced, but that will continue to increase. The probability of transmission also influences, how easy it is for a contact to end up in infection, which in turn depends on other things, such as the weather or how transmissible each variant is.
That complexity makes it difficult to say when group immunity will be achieved, assuming it’s possible. According UPC calculations for the European Union, with a level of contacts like the current one or a little higher, it would be enough to vaccinate 33% -50% of the people so that the virus would stop spreading and we would have that form of protection. But that would be maintaining restrictive measures, leading a normal life will require more vaccinated people, perhaps much more.
The most vaccinated: 40% of the population
Below we review how the incidence has evolved in different countries, as vaccination progressed. We start with the countries with the largest vaccinated population.
The most successful case is Israel. There the vaccination coincided with a strict confinement and the cases of covid-19 have practically reduced to zero. The advance in vaccination also coincides with a drop in cases in the United Kingdom, the United States, Mongolia and Chile, which have also vaccinated more than half of the people.
But the graph also shows us that severe outbreaks are possible with many vaccinated. This is what we see in Uruguay, a country that until November had successfully protected itself from the virus and that vaccinated quickly in the first months of the year, but which in mid-April registered large outbreaks in places as delicate as nursing homes. Also in Bahrain, where the incidence has rebounded with 40% of people vaccinated. This can occur due to heterogeneity – if certain social groups are not immunized – or by a sum of factors: if the newly vaccinated increase their interactions too soon, if other restrictions are relaxed or if the vaccines are not all equally effective.
In Chile, cases also rebounded in mid-March, when 30% of people had at least one dose. The strategy was then rethought as there was evidence that Sinovac, the vaccine that was being used the most, requires a second puncture early to achieve solid protection (with the first it stayed at 25% -30%, compared to 80% for Pfizer ). In this situation, like point tosome istudio, there was also an increase in contacts that facilitated the rebound. Now, two months later, infections in the country are going down again.
These figures recall the challenge that will be to recover a normal life, as Jeffrey Lazarus points out: “It will not be easy to continue growing once you have reached 50%. Already we are seeing that in the US There are many people who are unconvinced and, above all, dispersed in rural areas without the necessary sanitary infrastructure; or that younger people do not see as necessary or urgent to be vaccinated, as is happening in the United Kingdom ”.
Between 25% and 40%
The second group of countries that we have looked at are those where a third of the people have already received a dose. They are all European countries that, in addition to having similar vaccination levels, are coming out of winter, which is thought to help control the virus.
For the last graph we have focused on Latin America, where the virus has advanced at very different rates in recent months. Some countries in the south of the region have seen the incidence rise with the arrival of winter, such as Chile, Argentina and Uruguay. In Central America, cases have been declining lately, with the exception of Costa Rica, where they are rebounding.
The continent adds a variable to the puzzle: the extent of the most transmissible strains, such as the P1 detected in Brazil and later has jumped to many neighboring countries. This variant seems to spread more easily, although vaccines have been shown to be effective against it.
Having more people vaccinated will help mitigate the virus. But while vaccination advances, we will have to continue balancing: we will be able to recover contacts and relax restrictions, but only at the rate that the level of immunization, the transmissibility of the virus and its seasonality allow. The game will be easier than in recent months, perhaps increasingly permissive, but it will continue to be a juggling game for at least a while.