09 May 2023
Vaccine uptake and public health measures helped Mongolia control COVID-19, research finds
While the impact of COVID-19 in low- and middle-income countries remains understudied, new research by the Doherty Institute and the Mongolian National University of Medical Sciences has found that strong vaccine uptake and strict social measures were highly successful in containing COVID-19 in Mongolia between 2020 and 2021.
In the longitudinal study published in The Lancet Regional Health - Western Pacific, scientists tested blood serum between 2020 and 2021 to track the presence of total antibodies against SARS-CoV-2 in the Mongolian population. They found that, by the end of 2021, 82 per cent of people had developed antibodies to SARS-CoV-2 (antibody prevalence), compared to just 1.5 per cent in late 2020.
Data showed that the high antibody prevalence in the population at that time (known as seroprevalence) was largely due to the country’s successful vaccination program – by late 2021, 62 per cent of the country’s population had been vaccinated. Of those who were unvaccinated, nearly two thirds showed evidence of being infected with the virus by the end of 2021.
Joint co-first author of the study and Epidemiologist at the Doherty Institute, Dr Chris Bailie, said the research highlights the importance of vaccination in preventing severe disease.
“Mongolia’s early measures were very effective in preventing the spread of COVID-19, and then as restrictions were lifted, vaccination significantly constrained COVID-19 infections during the Delta outbreak,” Dr Bailie said.
“By the end of our study, more than 80 per cent of the population had shown evidence of antibodies from either vaccination or infection, and yet Mongolia still experienced a significant Omicron epidemic in early 2022.
“'This experience mirrored other highly immunised populations, like Australia, where despite high infection rates vaccines remained effective at reducing severe disease outcomes,” Dr Bailie said.
“So, it really emphasises the ongoing need for vaccination, and for looking at other public health measures, especially in low and lower middle-income countries, like Mongolia.”
The study also found that Mongolia’s COVID-19 epidemic characteristics were similar to those of other countries that had vaccinated their populations with inactivated SARS-CoV-2 vaccines, such as China.
However, there were differences in seroprevalence rates by age group, with children and adolescents aged under 15 having considerably lower seropositivity than adults by the end of 2021.
Joint author of the study and Director of Epidemiology at the Doherty Institute, Professor Jodie McVernon, said the collaboration with the Mongolian National University of Medical Sciences was an important step in building a strong scientific partnership.
“This project was an exciting opportunity enabled by our relationship with the WHO UNITY studies team in Geneva to collaborate with Mongolian colleagues on this ‘gold standard’ seroprevalence study,” Professor McVernon said.
Peer review: The Lancet Regional Health - Western Pacific https://doi.org/10.1016/j.lanwpc.2023.100760
Funding: World Health Organization, WHO UNITY Studies initiative, COVID-19 Solidarity Response Fund, German Federal Ministry of Health (BMG) COVID-19 Research and Development, Mongolian Ministry of Health.