WEDNESDAY, Dec. 16, 2020 (HealthDay News) -- Amid hopes stirred by the recent rollout of an approved COVID-19 vaccine in the United States, a new study warns that shots may not be available to nearly one-quarter of the world's people until 2022.
A second study estimates that 3.7 billion adults worldwide are willing to get the vaccine.
Together, these two findings suggest that getting people immunized could be as big a challenge as developing vaccines, especially in low- and middle-income countries.
"High-income countries have secured future supplies of COVID-19 vaccines, but that access for the rest of the world is uncertain," according to the researchers. "Governments and manufacturers might provide much needed assurances for equitable allocation of COVID-19 vaccines through greater transparency and accountability over these arrangements."
The first study reported that, as of Nov. 15, several countries had reserved 7.48 billion doses (or 3.76 billion courses) of vaccines being tested by 13 manufacturers.
The authors said that 51% of the doses were headed to wealthy countries, which have 14% of the world's population. Low- and middle-income countries -- home to more than 85% of the global population -- would potentially have access to the remaining doses, according to the report published online Dec. 15 in The BMJ.
In a best-case scenario, total projected manufacturing capacity would be 5.96 billion courses of vaccine by the end of 2021, with prices ranging from $6 to $74 per course, the researchers said in a journal news release.
Dr. Anthony So, of Johns Hopkins Bloomberg School of Public Health in Baltimore, led the study.
His team said up to 40% of available vaccine courses might remain for low- and middle-income countries, but that would partly depend on how wealthy nations share what they have access to. It would also hinge on whether the United States and Russia take part in internationally coordinated efforts.
Even if all vaccine manufacturers achieve maximum production capacity, at least one-fifth of the world's population would not have access to vaccines until 2022, the researchers said.
The second study, published in the same issue of the journal, found that 68% of adults worldwide (3.7 billion) are willing to get a COVID-19 shot.
"Variations in the size of the target populations within and between regions emphasize the tenuous balance between vaccine demand and supply, especially in low- and middle-income countries without sufficient capacity to meet domestic demand for COVID-19 vaccine," according to the team led by Hongjie Yu, of Fudan University in Shanghai, China.
Jason Schwartz, an assistant professor of public health at Yale University in New Haven, Conn., wrote an editorial that accompanied the findings.
While many countries have already committed to ensuring equal worldwide access to COVID-19 vaccines, Schwartz emphasized that vigilance is required "to ensure that such aspirations are realized in the months and years ahead."
Schwartz said successful, equitable implementation of the vaccines "requires unprecedented global coordination and a sustained commitment of resources -- financial, logistical, and technical -- from high-income countries."
The U.S. Centers for Disease Control and Prevention has more on COVID-19 vaccines.
SOURCE: The BMJ, news release, Dec. 15, 2020