The goal: Vaccinate 70% of the world against COVID. Scientists are proposing a reboot

When it comes to vaccinating people in middle- and lower-income countries against COVID-19, some global health advocates say it's time for a serious re-think.

"We seem to have lost perspective as to what the major goal of vaccines is and where they are going to yield the greatest public health benefit," says Shabir Madhi, a prominent vaccine researcher at South Africa's University of Witwatersrand.

Specifically, Madhi argues that governments in countries that still have low vaccination rates should shift their attention to vaccinating those who are most vulnerable to severe disease from the coronavirus. That means people age 50 and above or those with health conditions that put them at particular risk. The aim, says Madhi, should be to get 90% or more of people in this category vaccinated.

Unfortunately, he says, that effort is being hampered by a simultaneous push to meet a different goal – vaccinating 70% of all adults regardless of age or health status. It's an objective originally conceived by the World Health Organization, then embraced and promoted by the United States. But, says Madhi, it's a goal that could now be proving a harmful distraction.

The origin of the 70% goal

To understand why, it helps to consider how the 70% target emerged. Earlier on in the pandemic, the first results of mRNA vaccine trials suggested they would be extremely effective at preventing infection with COVID. This fueled hopes that if roughly 70% of a given country's population were vaccinated, it might be possible to drastically curb the spread of the virus there.

The World Health Organization initially proposed that the world ensure all countries meet the 70%-vaccinated target by mid-2022.Then, last September, President Biden convened a global summit at which he made the 70% goal a major priority and set a new deadline: fall of 2022.

Gayle Smith was then coordinator of the U.S. global COVID response. "Our thinking at the time was that the world had not embraced the level of ambition that was needed to really get moving on ramping up global vaccination coverage," says Smith.

Wealthy countries had taken 80% of the vaccine supply while in the lowest income countries less than 10% of people had gotten a jab.

Since then, largely due to a ramp up in donations — most significantly from the United States — the supply crunch has started to ease. But vaccination rates have remained dismally low. Taken together, in lower-middle income countries more than half of the population still hasn't gotten a vaccine. And in the poorest countries the needle has barely moved. Overall Africa is the hardest hit continent – with less than 13% of its overall population fully vaccinated. Also many countries have actually set their national goals to well below 70% – and yet they're not on track to meet even those lower targets.

At this point, says Smith, who is now CEO of the ONE Campaign, a global health advocacy group, for low-income countries, "I am less focused, quite frankly, on, 'will we get to 70% by September?' and more focused on, 'Can we get well over 9%? Can we get to 20, 30, 40, even 50%?"

The problem, says Smith, is that a lot more money is needed for the steps required to get shots into people's arms: storage, transportation, health workers, campaigns to counter misinformation.

Matt Linley is with Airfinity, an independent, London-based analytics company. He says because of those logistical barriers, on average low-income countries have only managed to use 45% of the doses they've gotten so far.

"So they're really struggling. Even with a smaller amount of supply, the issue is struggling to roll out the supply they have, rather than access."

Rethinking the global goal

Meanwhile, notes Madhi, the scientific thinking on the benefits of the 70% goal has evolved due to several developments. New variants mean the dominant strain of the virus is now much more transmissible than the earlier version. It's also become clear that immunity against infection wanes considerably over time. So to stop the virus from spreading in a country, you'd have to vaccinate much more than 70% of its population. "The calculus has changed completely," says Madhi.

On the plus side, immunity against severe disease has proven durable. And so, there's been a widespread adjustment in discussion of the purpose of vaccines – with the emphasis less on how much they limit transmission and much more on how they can serve to protect populations from the worst impacts of COVID. In that light, says Madhi, it makes sense for countries with limited resources to devote them to vaccinating those most at risk.

"That will be a much more efficient use of vaccines and a more efficient use of resources," he says.

Madhi adds that this is even more the case in countries where, due to various large COVID waves over the course of the pandemic, more than 70% of the population has now effectively been immunized through prior exposure. In South Africa, this immunity was gained through "a huge cost in lives – close to 300,000 lives were lost because of COVID-19," he notes. So it's not the route anyone would have advocated. But now that it's the reality in South Africa and so many other nations, Madhi argues it's one more reason for an all-out push to focus on vaccinating the most vulnerable.

Madhi says he's hardly the only one making this case. The Strategic Advisory Group of Experts on Immunization, one of the main groups that informs the World Health Organization's decisions, "has repeated on many occasions that it is people above age 50 that need to be prioritized," says Madhi. Yet because WHO continues to emphasize the 70%-of-all-adults goal, he says, "there is a disconnect. They don't really speak from the same page."

The mixed message is particularly damaging in countries where progress toward vaccination remains slow.

Take his own nation of South Africa. The government's current vaccine strategy is "sort of random," says Madhi. It's not that the government isn't aware of the importance of targeting the 50-plus group. Indeed, it's even offering them monetary incentives such as food vouchers to get a jab.

But South Africa appears at least equally and arguably even more focused on getting shots into the arms of people of any age, says Madhi. "Right now it's doing both things" – and succeeding at neither. South Africa's overall vaccination rate remains stuck at 30% and among the over-age-50 group only about 63% have been fully vaccinated.

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