According to a new modeling study published in The Lancet Infectious Diseases, COVID-19 vaccines are estimated to have prevented 20 million deaths worldwide in the first year of the vaccine program.
- The first model study to quantify the impact of vaccines against COVID-19 globally estimates that 19.8 million of the potential 31.4 million deaths were prevented in the first year after the introduction of the vaccines (8 December 2020 – 8 December 2021).
- Another 599,300 deaths could have been avoided if the World Health Organization’s goal of vaccinating 40% of the population in each country by the end of 2021.
- High- and higher-middle-income countries account for the highest number of prevented deaths (12.2 million / 19.8 million), highlighting inequalities in access to vaccines worldwide.
- The study is based on data from 185 countries and territories and is the first to estimate deaths prevented directly and indirectly as a result of vaccination against COVID-19, using data on deaths from COVID-19 and the total number of deaths from each country (or estimates where official data was not available).
COVID-19 vaccines have reduced the potential global number of deaths during a pandemic by more than half in the year following their implementation, according to estimates from a mathematical modeling study published on June 23, 2022 in The Lancet Infectious Diseases.
19.8 million of the potential 31.4 million deaths from COVID-19 were prevented worldwide in the first year of the vaccination program, according to estimates based on over-deaths from 185 countries and territories.
Researchers estimate that another 599,300 lives could be saved if the World Health Organization’s goal is to vaccinate 40% of the population in each country with two or more doses by the end of 2021.
Dr Oliver Watson, lead author of the study from Imperial College London, said: “Our findings offer the most complete assessment to date of the remarkable global impact of vaccination on the COVID-19 pandemic. Of the nearly 20 million deaths estimated to have been prevented in the first year after the introduction of the vaccines, almost 7.5 million deaths have been prevented in countries covered by the COVID-19 Vaccine Access Initiative (COVAX) . This initiative was created because it was clear at the outset that global vaccine justice would be the only way out of the pandemic. Our findings show that millions of lives have probably been saved by providing vaccines to people everywhere, regardless of their wealth. However, more could be done. If the goals set by the WHO were achieved, we believe approximately 1 in 5 of the life expectancy lost due to COVID-19 in low-income countries could be prevented. ”
Since the first COVID-19 vaccine was administered outside the clinical trial on 8 December 2020, almost two thirds of the world’s population has received at least one dose of COVID-19 vaccine (66%). The COVID-19 Vaccine Access Initiative (COVAX) has facilitated access to affordable vaccines for lower-income countries in an attempt to reduce inequalities, with the initial aim of giving two doses of vaccine to 20% of the population in the countries, covered by the end-2021 commitment, the World Health Organization has expanded this goal by setting a global strategy to fully vaccinate 70% of the world’s population by mid-2022, with an intermediate target of vaccinating 40% of the population in all countries by end of 2021
Despite the incredible speed with which the vaccine has been introduced worldwide, more than 3.5 million deaths have been reported from COVID-19 since the first vaccine was given in December 2020.
Several studies have attempted to assess the impact of vaccination on the course of the pandemic. These studies focus on specific regions, such as individual countries, states, or cities. The latest study is the first to assess the impact of COVID-19 vaccinations globally and the first to assess the number of deaths prevented, both directly and indirectly.
Mr Gregory Barnsley, co-author of the study from Imperial College London, said: “Quantifying the impact of vaccination worldwide is a challenge because access to vaccines varies from country to country, as well as our understanding of which options of COVID-19 have circulated, with very limited data on genetic sequences available for many countries. It is also not possible to directly measure how many deaths would occur without vaccinations. Mathematical modeling offers a useful tool for estimating alternative scenarios that we cannot directly observe in real life.
To assess the impact of global vaccination programs, the researchers used an established model of COVID-19 transmission, using country-level data on officially registered COVID-19 deaths between 8 December 2020 and 8 December 2021. To take into account the under-reporting of deaths in countries with weaker surveillance systems, they carried out a separate analysis based on the number of reported over-deaths over those that would have been expected over the same period. When official data were not available, the team used estimates of over-mortality for all reasons. These analyzes were compared with an alternative hypothetical scenario in which no vaccines were delivered.
The model takes into account variations in vaccination levels between countries, as well as differences in the efficacy of vaccines in each country based on the types of vaccines known to have been used mainly in these areas. In particular, China was not included in the analysis due to its large population and very strict blocking measures, which would distort the findings.
The team found that, based on officially registered deaths from COVID-19, approximately 18.1 million deaths would have occurred during the study period if no vaccinations had been given. Of these, the model estimates that vaccination has prevented 14.4 million deaths, a global reduction of 79%. These findings do not explain the under-reporting of COVID-19 deaths, which is common in lower-income countries. The team performed additional analysis based on the total over-deaths over the same time period to account for this. They found that vaccination against COVID-19 prevented approximately 19.8 million deaths out of a total of 31.4 million potential deaths that would have occurred without vaccination, a reduction of 63%.
More than three-quarters (79%, 15.5 million / 19.8 million) of the deaths prevented were due to the direct protection against severe symptoms provided by vaccination, leading to lower mortality rates. The remaining 4.3 million prevented deaths are estimated as prevented by indirect protection against reduced transmission of the virus to the population and reducing the burden on health systems, thus improving access to medical care for those most in need.
The impact of the vaccine has changed over time and in different parts of the world as the pandemic progresses, the study found. In the first half of 2021, the highest number of deaths avoided by vaccination was observed in countries with lower average incomes, as a result of the significant epidemic wave in India when the Delta option appeared. This subsequently shifted to the largest impact, which was concentrated in higher-income countries in the second half of 2021, as restrictions on travel and social mixing were eased in some areas, leading to greater transmission of virus.
Overall, the number of prevented deaths per person is highest in high-income countries, reflecting the earlier and wider deployment of vaccination campaigns in these areas (66 prevented deaths per 10,000 people in high-income countries against 2,711 prevented deaths per 10,000 people in low-income countries). High- and higher-middle-income countries account for the highest number of avoided deaths (12.2 million / 19.8 million), highlighting inequalities in access to vaccines worldwide.
For the 83 countries included in the analysis, which are covered by COVAX’s commitment to affordable vaccines, approximately 7.4 million deaths were avoided by a potential 17.9 million (41%). However, failure to meet COVAX’s goal of fully vaccinating 20% of the population in some countries is thought to have resulted in an additional 156,900 deaths. Although this figure represents a small proportion of total deaths worldwide, these preventable deaths are concentrated in 31 African countries, where 132,700 deaths could have been prevented if the target had been achieved.
Similarly, the failure of the WHO target to fully vaccinate 40% of each country’s population by the end of 2021 is thought to have contributed to an additional 599,300 preventable deaths worldwide. Lower middle income countries account for the majority of these deaths (347 500/599 300 [59.7%]). Regionally, most of these deaths are concentrated in the African and Eastern Mediterranean regions (348 900/599 300 [58.2%] and 126,800 / 599,300 [21.2%] respectively). If the 40% target had been achieved in all low-income countries, the number of deaths prevented by vaccination in these areas would have doubled (200,000 additional deaths have been prevented in addition to the 180,300 deaths estimated, that they were prevented at current vaccination levels).
Prof. Azra Ghani, President of Infectious Diseases Epidemiology at Imperial College London: “Our study demonstrates the enormous benefits of vaccines in reducing COVID-19 deaths worldwide. Although the intense focus on the pandemic has now shifted, it is important to ensure that the most vulnerable people in all parts of the world are protected from the continued circulation of COVID-19 and other major diseases that continue to disproportionately affect the poorest. Ensuring fair access to vaccines is crucial, but it requires more than just donating vaccines. Improvements in vaccine distribution and infrastructure, as well as coordinated efforts to combat vaccine misinformation and improve vaccine demand, are …
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