DAKAR, Senegal — In the pandemic's early days, scientists across Africa were certain: They did not want to rely on vaccines from abroad. Richer countries could hoard supplies, they feared, leaving nations with tighter research budgets behind.

“They don’t have the vested interest in African people like we living here do,” said Christian Happi, whose laboratory in southwestern Nigeria aims to complete its own inoculations.

The mission feels especially urgent, he said, as vaccinations begin in the United States, Europe and elsewhere. Public health officials warn that stark disparities are emerging as wealthier countries reserve most of the world’s doses, while poorer countries have secured scarce amounts.

By mid-November, wealthy nations had reserved 51 percent of various vaccine doses even though they are home to only 14 percent of the world’s population, according to a new study by two Johns Hopkins researchers in the BMJ, a trade journal published by the British Medical Association.

Ending outbreaks in resource-strapped areas is vital to crushing the coronavirus for good, health officials say: As long as the contagion exists somewhere, it can continue to seed and circulate.

Distribution campaigns across Africa are not likely to begin until April, the head of the Africa Centers for Disease Control and Prevention estimated. Even then, far fewer doses will be sent to African countries than are being shipped to the United States and Europe.

“It will be extremely terrible to see,” said John Nkengasong, the Africa CDC director.

Most of Africa’s 54 nations stand to benefit from the Covid-19 Vaccines Global Assess Facility, or Covax, the World Health Organization-backed program set to divide a billion doses across 92 low- and middle-income countries next year. But $5 billion more is needed to cover vulnerable residents in target nations by the end of 2021, according to Gavi, the alliance raising funds for Covax.

“Africa is often holding the short end of the stick,” said Ahmed Ogwell Ouma, deputy director of the Africa CDC.

There was no evidence of direct deals between companies such as Pfizer and the globe’s poorest countries, researchers from Duke University wrote in early December, suggesting that huge numbers of people will be “entirely reliant” on Covax.

The United States has locked in 800 million doses, more than enough to inoculate its entire population, according to the study published in the BMJ. Low-income countries have collectively reserved 100 million fewer than that.

“High income countries have secured future supplies of covid-19 vaccines,” the authors wrote, “but that access for the rest of the world is uncertain.”

If conditions do not change, 67 nations will be able to vaccinate only 1 in 10 people over the next year, according to a report this month from the People’s Vaccine Alliance, a nonprofit coalition that includes Amnesty International and Oxfam International.

For months, leaders across Africa have called for a more equal path to recovery.

“Nobody should be pushed to the back of the vaccine queue because of where they live or what they earn,” South African President Cyril Ramaphosa said in May.

Nigerian President Muhammadu Buhari said in October that “a bold international agreement cannot wait.”

Africa has shouldered a tiny share (3.4 percent) of the globe’s coronavirus infections. Researchers attribute that to several factors: doctors and nurses with epidemic experience, early lockdowns, the continent’s youth — almost 60 percent of sub-
Saharan Africans are younger than 25 — and a unique landscape of pathogens. (Fatality rates have been higher in South Africa, Algeria, Egypt and Tunisia, which have older populations.)

There are hundreds of vaccine candidates at different stages of development worldwide, a WHO database shows. None in Africa have reached clinical trials.

Funding is the top barrier for Happi, the director of the African Center of Excellence for Genomics of Infectious Diseases in Ede, Nigeria.

His formula was 90 percent effective in animal trials, he said, but the lab has not secured the money to move on to humans. Nigeria’s central bank has earmarked cash for vaccine development, but only about $1.3 million is available to complete the process. Finishing a drug often requires hundreds of millions of dollars.

Then there are the logistical challenges around what will amount to the largest immunization drive in Africa’s history. A WHO analysis, based on self-reporting from 47 nations in November, found that the region has an average score of 33 percent readiness for a vaccine rollout — well below the 80 percent goal.

One issue is a lack of cold rooms and other high-tech freezers for imported drugs. Pfizer’s vaccine, for instance, must be kept at minus-94 degrees Fahrenheit (minus-70 Celsius). That is a particularly huge task in areas that lack reliable electricity.

Some airlines already have the frigid-transport technology. Ethiopian Airlines has announced plans to fly coronavirus vaccines throughout Africa.

Misinformation, however, has fueled skepticism around treatments from overseas. Social media exploded in outrage this summer after a French doctor suggested in a televised interview that new drugs be tested in African nations.

Health officials continue to stress the importance of clinical trials in Africa. Vaccines must be tested across different populations, they say, to ensure efficacy for everyone.

“The majority of our building materials are the same, but the differences could impact how things affect us,” said Moses Bockarie, honorary chief specialist scientist at the South African Medical Research Council.

South Africa, Egypt and Kenya have enrolled people in trials of Western-made vaccines. The vaccine developed by AstraZeneca and the University of Oxford seems to be the best candidate for most African countries because it can be transported at refrigerator temperature, said Shabir Madhi, a professor of vaccinology at the University of the Witwatersrand in Johannesburg who co-authored a peer-
reviewed study of the trial
.

Happi longs to see more local solutions — something people might be more likely to trust.

His team created a DNA-based vaccine that factored in viruses circulating the continent, as well as the genetic makeup of immune systems here.

“You can’t develop a vaccine based on the responses of people in New York or Paris or Berlin,” he said, “without understanding how it will work for African people.”

Bearak reported from Nairobi.