In the United States, as of January 24, 2023, the number of deaths due to the novel coronavirus infection (COVID-19) has passed 1.1 million.breakthroughand has the highest number of casualties in the world. Seeing so many deaths in the United States, which developed a vaccine ahead of the world and promoted vaccination by raising the country, people who wonder, “After all, vaccines were meaningless?” There may be others, but a study reported that if there was no vaccine, the death toll in the United States would have quadrupled.
Two Years COVID Vaccines Prevented Millions Hospitalizations Deaths | Commonwealth Fund
US COVID death toll would be 4X higher without vaccines, modeling study finds | Ars Technica
In the United States, more than 655 million doses of the new coronavirus vaccine have been administered since December 2020, with 80% of the population receiving at least one dose. To verify the effectiveness of these vaccination programs, a team led by Allison P. Galvani of the Yale Center for Infectious Disease Modeling and Analysis modeled and simulated the impact of the COVID-19 pandemic and vaccines.
The ‘age-stratified, pathogen-based model of COVID-19’ used by the research team included COVID-19 risk by age, U.S. demographics, prevalence of comorbidities, pandemic policy and contacts that accounted for the movement of people. It includes various parameters such as patterns, efficacy of vaccines, and reduction in immunity conferred by vaccination or infection. In addition to the original Wuhan strain, five mutant strains of the new coronavirus (SARS-CoV-2) were assumed: the Iota strain, the alpha strain, the gamma strain, the delta strain, and the Omicron strain.
Using this model, we conducted a simulation comparing the “counterfactual scenario” of what would happen if there was no vaccine and the trajectory of the actually observed pandemic. Between December and November 2022, vaccination prevented 3.25 million deaths, averted 119.85 million infections and 18.6 million hospitalizations. I was.
Below is a graph comparing COVID-19 infected people per 100,000 population in the United States (orange line) and the no-vaccination scenario (blue dashed line).
With 798,000 COVID-19 deaths, 82 million cases, and 4.8 million hospitalizations during the same period, deaths are 4.1 times higher and infections are 1.5 times higher without a vaccine. , the number of hospitalized patients increased 3.8 times, and it is estimated that the additional necessary medical expenses reached 1 trillion dollars (about 130 trillion yen).
The simulation showed that the vaccine prevented tens of millions of COVID-19 infections, which is said to be more significant than the numbers. This is because COVID-19 has risks such as “long COVID”, which has long-term effects on cognitive functions and other factors even after recovery, and physical strength decline.
Pointed out that “long COVID”, in which the symptoms of the new coronavirus last for a long time, is more dangerous than is known-GIGAZINE
Given the occurrence of multiple variants, the effectiveness of the vaccination program becomes more pronounced. In particular, the Omicron strain has a high ability to evade immunity, and the emergence of this mutant strain caused a spike in the number of COVID-19 cases, but the vaccine also prevented hospitalization and death of infected people. Galvani and his colleagues point out that some reports that “the Omicron strain is mild” are largely due to the protection provided by the vaccine.
On top of that, the research team said, “The unprecedented pace of vaccine development and deployment has saved many lives, eased restrictions on COVID-19 measures to make it safer, and allowed businesses, schools, and other activities to continue. It has been resumed. Going forward, how to accelerate the booster vaccination will be the basis for avoiding the occurrence of severe cases and deaths in the future.”
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