Just over 2% of people in low-income countries have received any Covid-19 vaccines.

Editor’s Note: The author is the co-chair of the Bill & Melinda Gates Foundation. The views expressed here are his own. View more opinion on CNN.

CNN  — 

Today, 46% of the world’s population has received at least one dose of a Covid-19 vaccine. It’s hard to overstate what a remarkable achievement this is. Humanity has never made and distributed a vaccine for a disease faster than it did for Covid-19. It accomplished in 18 months something that used to take a decade or more.

But within this amazing success, there is a startling disparity: Just over 2% of people in low-income countries have received any Covid-19 vaccines. And the gap will be harder to close as the world’s richer governments buy up extra doses to serve as booster shots.

Bill Gates

People are right to be upset about the inequity here. Vaccines make Covid-19 a largely preventable disease – and a survivable one in all but the rarest cases – and it is heartbreaking to know that people are dying of a disease not because it can’t be stopped but because they live in a low-income country.

Sadly, this inequity is not new. It is not even the worst gap in global health. There were shocking disparities in health long before any of us had heard of Covid-19.

Every year, more than 5 million children die before their fifth birthday, mostly from infectious diseases, and almost entirely in low- and middle-income countries. A child in northern Nigeria is more than 20 times more likely to die before the age of 5 than a child in a rich country. That is simply unjust and reducing this inequity has been the Gates Foundation’s top priority for more than 20 years.

If you step back and look at the trends, though, there is good news. Since 1960 the childhood death rate has been cut by more than 80%, thanks in large part to the invention and distribution of vaccines for children around the world.

The fact that routine childhood vaccines are reaching so many people is reason to believe Covid-19 vaccines can too.

Providing them to everyone who needs them is one of three crucial steps in controlling this pandemic, along with containing the virus so it doesn’t come roaring back and coordinating the global response.

At the same time, we can learn from the inequities that were so clear during this pandemic so we can do a better job of closing the gap during the next one. (Assuming there is a next pandemic. I think it is possible to prevent them altogether. But that’s a subject for another time.)

How could we achieve vaccine equity in a future pandemic? I see two ways:

Change how the world allocates doses

What would the optimal allocation look like? It’s not simply a matter of proportional representation, where if your county has X percent of the world’s population, you get X percent of the vaccines. There are two different benefits to consider, and both are important.

One benefit is to the individual who’s immunized; they get protection from the virus. The more likely you are to get infected – and the more likely you are to become seriously ill or die if you do get infected – the more benefit you get from a vaccine.

A 70-year-old Covid-19 patient is 90 times more likely to die than an otherwise healthy Covid patient in their 20s. From a global perspective, it is neither fair nor wise to protect that young person before the old one.

Second, when an individual is vaccinated, society gets the benefit of lowering the risk that the person will spread the disease to others. This is the core of the argument in favor of vaccinating health workers and people who work in elderly care facilities, since even when a lockdown is in place, they can transmit the virus to people at high risk.

When a virus is spreading, we should maximize both benefits – saving lives and stopping transmission. This means that, when supplies are short, we should prioritize vaccinating people who both have a high risk of death and live in the places where the virus is spreading fastest.

Those will not necessarily be low-income countries. When Covid-19 vaccines first became available, many of the most severe epidemics were in rich- and middle-income countries.

The gravest inequity, even more than vaccinating rich people before poor ones, is vaccinating young people in rich countries before older people in middle-income countries with bad epidemics, such as South Africa and most of South America.

To their credit, rich countries have pledged to share more than a billion doses with poorer countries during Covid-19. But they haven’t yet delivered fully on those pledges, and even if they had, the gap would still be enormous.

Although sharing doses needs to be part of the solution, it will never be sufficient to solve the problem. For one thing, the number of doses won’t be high enough. And will future politicians always be willing to tell young voters they can’t be vaccinated because the doses are going to another country, at a time when schools are still closed and people – including a few young people – are still dying?

That’s why it’s so important to find ways to produce more doses in less time. The world should have the goal of being able to make and deliver enough vaccines for everyone on the planet within six months of detecting a potential pandemic. If we could do that, then the supply of doses would not be a limiting factor, and the way they were allocated would no longer be a matter of life and death.

Make more doses

As limited as the supply of Covid-19 vaccines has been, the situation could have been even worse.

We are fortunate that mRNA vaccines work so well, since this is the first disease for which the mRNA technology has been used. If they hadn’t, we would have been far worse off.

It is also great that some vaccine companies entered into second-source deals, which allowed huge volumes of their vaccines to be manufactured by other firms. This was a crucial and remarkable step. (It’s as if Ford let Honda use its factories to build Accords.) Just one example: In less than two years, a single manufacturer, AstraZeneca, signed second source deals involving 25 factories in 15 countries.

You may have heard the argument that waiving intellectual property (or IP) restrictions would have made a difference. Unfortunately, that’s not true in this case. IP waivers and licensing are complicated issues, so I want to take some time to untangle it.

There are cases in which IP licensing is a great way to make something cheaper and better. For example, in 2017, the Gates Foundation and a number of partners were involved in an agreement to make a new, more effective version of an HIV drug cocktail that would be more affordable for the world’s poorest countries.