COVID-19 vaccination reduces hospitalization and death rates in the UK

Many people around the world are aware that the 2019 coronavirus disease (COVID-19) pandemic has prompted intensive and widespread efforts by governments and the private sector alike to develop a nationwide vaccine and vaccination programmes. We’re still debating whether it’s worth paying for.new research published medRxiv* A preprint server examines hospitalization and mortality from COVID-19 before and after vaccine deployment in the UK.

study: Estimating the efficacy of COVID-19 vaccination against COVID-19 hospitalizations and deaths: a cohort study based on the UK 2021 Census. Image credit: Looker Studio / Shutterstock.com

*Important Notices: medRxiv Publishes preliminary scientific reports that have not been peer-reviewed and should therefore not be considered definitive, to guide clinical practice or health-related actions, or to be treated as established information. not.

About research

In early December 2020, Pfizer/Biontech’s novel coronavirus disease (COVID-19) messenger ribonucleic acid (mRNA) vaccine was introduced in the UK, followed by Moderna’s mRNA vaccine and Oxford/AstraZeneca’s adenoviral vector vaccine ChAdOx1. -S was introduced. Clinical trials of each of these vaccines have demonstrated high vaccine efficacy (VE) in preventing symptomatic and severe COVID-19.

In the current study, researchers are looking at population-level data from the UK’s 2021 Census of over 580,000 people aged 16 and over.

Data from individuals who received 1, 2, or 3 doses of vaccine were examined and stratified by time after each dose. The main outcome of this study was to use unvaccinated participants as controls and to assess the likelihood of hospitalization in vaccinated participants at different time points after each exposure and after each administration.

VE for hospitalization

One dose of COVID-19 vaccine reduced the likelihood of hospitalization by 52%, but two doses increased VE to 56%.

VE for hospitalization due to COVID-19 was negative for more than 3 months after the first vaccination, regardless of age. However, after the second dose, it was highest in people aged 30-64 and 65-79. After the third booster, VE peaked at approximately 88% in the 65-79 year old group.

After 3 doses, the risk of hospitalization was reduced by almost 78%. The protection provided by the full first course plus his third booster dropped to approximately 68% when he was more than three months after the third dose. At this time her VE decreased the most in people aged 30-64.

VE for mortality

After one dose of vaccine, the risk of death was reduced by almost 60%. A notable exception was those aged 80 years and older, who had nearly zero VE with one dose. After the second dose, protection increased to 90% overall. However, compared with high VE in individuals aged 30-79 years, VE remained low in those aged 80 and over.

The highest VE of 93% was observed after booster administration. However, people between the ages of 16 and 29 showed 71% VE. In addition, VE decreased more than 3 months after the 2nd and 3rd doses, but remained high except in the 16-29 year group, where it decreased significantly. Did.

VE by variant

During the Omicron wave, the COVID-19 vaccine protected individuals from hospitalization better than previous reports. However, the VE for mortality decreased.

In addition, VE for hospitalization was higher after the second dose than after the first or third dose during omicron waves. However, all VEs declined from 3 to 6 months, and decreased further to approximately 40% at 6 months after the second dose.

After the third dose, the rate of protection against hospitalization decreased from 80% before onset of omicron waves to 55% thereafter. However, the 23% decrease in VE observed 3 months after the third pre-Omicron dose did not occur during the Omicron wave.

Covid-19 mortality decreased after the 1st, 2nd and 3rd vaccinations during the Omicron dominance period. In fact, the first dose was not significantly protective, but after the second dose, the VE for mortality decreased to approximately 50% at 6 months.

VE by vaccine type

Overall, mRNA vaccines performed better than other COVID-19 vaccines. However, the population protected in each case was different. The mRNA vaccine showed a reduction in VE for hospitalization over 3 months after the boost, whereas both vaccine types showed a reduction in VE for death over 3 months after his second dose.

confounder

Confounding factors may have influenced the calculation of VE for mortality from causes other than COVID-19.

A possible source of error may be the administration of vector-based vaccines to the most frail and high-risk patients and the vaccination of healthy individuals with more effective vaccines. Follow-up for this study began in late March 2021, but the vaccination campaign began on December 8, 2022.

Therefore, the oldest in this study may have been frail or did not have access to vaccination sites at the start of the campaign. This affected the likelihood of developing severe or fatal COVID-19 after the first dose.

Possibly because these people are elderly and medically ill people whose vaccination was delayed due to health concerns, the lower VE after the first and second doses is likely explained by frailty bias. .

Likewise, younger, healthier people are more likely to get boosters later. As a result, follow-up 3-6 months after booster and >6 months is skewed toward high-risk individuals. These findings indicate that health status is an important confounder after adjusting for other factors.

Given the inconsistent decline across the breakdown, there is no strong evidence that protection against COVID-19 hospitalization is weakening. There is a consistent decrease in VE for COVID-19 mortality across different breakdowns.This may indicate reduced protection”

What is the impact?

Vaccine efficacy estimates show increased protection with number of doses, with the third/boost dose providing high levels of protection against both hospitalization and mortality from COVID-19. It has been.”

For the first time, the current study used 2021 Census data to adjust for socioeconomic and health status variables, thereby improving the accuracy of real-world VE estimation. Nonetheless, residual confounding by health status is observable and should be factored into VE estimation tools in future studies.

*Important Notices: medRxiv Publishes preliminary scientific reports that have not been peer-reviewed and should therefore not be considered definitive, to guide clinical practice or health-related actions, or to be treated as established information. not.