The storage of vaccines by countries can have a significant impact on the global trajectories of the number of COVID-19 cases and increase the potential emergence of new variants of the SARS-CoV-2 virus, a modeling study has warned.
The research, published Tuesday in the journal Science, explored the effects of different vaccine sharing programs on the global persistence of COVID-19 infections, as well as the possibility of new variants evolving, using mathematical models. .
The researchers noted that the allocation of preventive COVID-19 vaccines between countries has so far tended towards vaccine nationalism, in which countries stockpile vaccines to prioritize access for their citizens rather than equitable sharing of vaccines.
“Some countries that have experienced severe outbreaks of COVID-19 have received few vaccines, while many doses have gone to countries with comparatively milder pandemic impacts, either in terms of mortality or economic disruption,” said co-first author of the study, Caroline Wagner, assistant professor at McGill University in Canada.
“As expected, we have seen a sharp decrease in the number of cases in many regions where access to vaccines is high, but infections are reappearing in areas with low availability,” studied co-lead author Chadi Saad-Roy , a graduate student from Princeton University in the United States, added.
Researchers projected the incidence of COVID-19 cases under a range of vaccine dosing regimens, vaccination rates, and assumptions related to immune responses.
They did this in two model regions: one with high access to vaccines – a high access region (HAR) – and a low access region (LAR).
The models also made it possible to couple the regions either by importing cases or by developing a new variant in one of the regions.
The study found that increased vaccine sharing resulted in a reduction in the number of cases in ARL.
“Because vaccines appear to be very effective in reducing the clinical severity of infections, the public health implications of these reductions are very significant,” said study co-author Michael Mina, assistant professor at Harvard TH Chan School of Public. Health, United States.
Lead author of the study, C Jessica Metcalf, associate professor at Princeton, noted that a high number of cases in unvaccinated populations is likely to be associated with a higher number of hospitalizations and greater clinical burdens. compared to highly vaccinated populations.
The authors also drew on a framework developed in their previous work to quantify the potential for viral evolution in the context of different vaccine sharing programs.
In their model, repeated infections in individuals with partial immunity – either from a previous infection or from a vaccine – resulted in the development of new variants.
“Overall, the models predict that a high number of cases in LARs with limited vaccine availability will lead to a high potential for viral progression,” said lead author of the study, Bryan Grenfell, member. Associate Professor of the High Meadows Environmental Institute (HMEI), Princeton. .
“The study strongly underscores the importance of rapid and equitable global distribution of vaccines,” Grenfell said.
The researchers noted that in a scenario where secondary infections in individuals who have previously been infected strongly contribute to viral progression, uneven allocation of vaccines appears particularly problematic.
Global vaccine coverage will reduce the clinical burden of new variants, while also decreasing the likelihood that these variants will emerge, they added.
(This story was not edited by Devdiscourse staff and is auto-generated from a syndicated feed.)