The coronavirus disease 2019 (COVID-19) pandemic caused over 438 million documented cases, with over 5.96 million deaths worldwide. The high number of deaths within a year of the onset of the outbreak spurred the development of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with the Pfizer-BioNTech messenger ribonucleic acid (mRNA) vaccine being the first to receive emergency use authorization (EUA) in the USA.
With billions of doses having been rolled out in that country, a new study shows the impact of the vaccine program on the state of public health in the USA. This is important in shaping future decisions about vaccination as a public health strategy and on a personal level.
Both randomized clinical trials (RCTs) and real-world data show that the COVID-19 vaccines have high effectiveness against SARS-CoV-2 infection and severity of illness. The greatest effect was on the number of symptomatic infections, deaths, and hospitalizations.
The current study, published on the medRxiv* preprint server, discusses the cost-effectiveness of the vaccine strategy using the Pfizer vaccine as the index intervention. Earlier research has explored this aspect with respect to the healthcare system. In addition, this study examines the effects of vaccination with the Pfizer vaccine on productivity, and its economic impact, using data from multiple studies of high quality for quantitative analysis.
The researchers aimed to find the public health impact of this vaccine at one year, using a combination of statistical methods. The target group comprised the US population aged 12 years and above, with information on the clinical features, the type, number and location of contacts, the spread of the virus, economic and human behavioral factors being used to analyze the vaccine impact on this group.
Vaccine coverage was derived from official data, while various studies were mined for data on vaccine efficacy following one or two doses of this vaccine, as well as the duration of protective vaccine-induced immunity.
The various outcomes investigated included the number of deaths and symptomatic cases avoided, both outpatient and inpatient cases. The economic results were estimated by the quantitative reduction in healthcare utilization and the reduced costs to society.
What did the study show?
The researchers estimated 12% prior infection with the virus among the vaccine-eligible US population, that is, about 33 million. Without vaccination, about a quarter of the susceptible eligible population would have been infected, they estimated, during 2021.
Approximately 60% would be due to the Delta strain, while over a fifth would have been caused by the ancestral strain. Over one in seven was caused by Alpha, and 2% by Gamma. Overall, they estimated that 3.5 million hospitalizations would have occurred without vaccination and almost half a million deaths.
The official tracker of the Centers for Disease Control and Prevention (CDC) shows very similar estimates. Thus, the primary series of the Pfizer vaccine prevented about 8.7 million symptomatic cases, 690,000 hospitalizations, and 110,000 deaths from COVID-19.
Over 77% of deaths, and almost 55% of hospitalizations, were among the elderly aged 65 years of age or more, who experienced less than a fifth of the deaths. Almost 73% of hospital stays were not associated with mechanical ventilator use, while a quarter were in the intensive care unit (ICU). Of the latter, more than half required mechanical ventilation, compared to 5% of those in a normal ward.
The vaccine is estimated to have increased the number of life-years and Quality Adjusted Life Years (QALYs) by over a million, mostly by averting COVID-19-related deaths. A lower effect was due to a reduction in symptoms of infection and the chronic adverse effects of mechanical ventilation.
Productivity was gained, to the tune of $44 billion, with over a third of this being due to less productivity lost by premature deaths and two-thirds due to reduction in absence from work due to symptomatic COVID-19.
What are the implications?
According to these findings, the Pfizer vaccine is linked to a large impact on public health in the USA. The mechanisms include averting millions of symptomatic COVID-19 cases, thousands of hospitalizations, and thousands of deaths. In direct correlation with these effects, billions of dollars were seen to have been saved directly by avoiding healthcare-related payments and indirectly via averting losses in productivity.
This agrees with other studies that have shown vaccination reduces the societal burden of COVID-19. It shows that even without regard to the indirect benefits of vaccination, such as reduced viral transmission and the opening up of businesses and public places as immunity approaches population immunity levels.
This is the first study to assess multiple outcomes following vaccination using several types of data, including clinical severity, epidemiological characteristics, economic parameters, and others, to arrive at an estimate of the public health impact of this vaccine in the US population. However, it did not include children or certain high-risk groups who did not respond as expected to the vaccine.
The findings of this study may not fully reflect the current or future disease trends (e.g., prevalence of Omicron variant), vaccine clinical profile, healthcare resource use and costs. As COVID-19 data continues to rapidly expand and evolve, future studies are warranted to assess the public health impact in those additional settings as well as in the longer-term.”
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.