Dataset Information

Effect of influenza vaccination on excess deaths occurring during periods of high circulation of influenza: cohort study in elderly people.

ABSTRACT:

Objective

To estimate the protection against death provided by vaccination against influenza.

Design

Prospective cohort follow up supplemented by weekly national counts of influenza confirmed in the community.

Setting

Primary care.

Participants

24,535 patients aged over 75 years from 73 general practices in Great Britain.

Main outcome measure

Death.

Results

In unvaccinated members of the cohort daily all cause mortality was strongly associated with an index of influenza circulating in the population (mortality ratio 1.16, 95% confidence interval 1.04 to 1.29 at 90th centile of circulating influenza). The association was strongest for respiratory deaths but was also present for cardiovascular deaths. In contrast, in vaccinated people mortality from any cause was not associated with circulating influenza. The difference in patterns between vaccinated and unvaccinated people could not easily be due to chance (P = 0.02, all causes).

Conclusions

This study, using a novel and robust approach to control for confounding, provides robust evidence of a protective effect on mortality of vaccination against influenza.

SUBMITTER: Armstrong BG

PROVIDER: S-EPMC517645 | biostudies-literature | 2004 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Effect of influenza vaccination on excess deaths occurring during periods of high circulation of influenza: cohort study in elderly people.

Armstrong Ben G BG Mangtani Punam P Fletcher Astrid A Kovats Sari S McMichael Anthony A Pattenden Sam S Wilkinson Paul P

BMJ (Clinical research ed.) 20040815 7467

<h4>Objective</h4>To estimate the protection against death provided by vaccination against influenza.<h4>Design</h4>Prospective cohort follow up supplemented by weekly national counts of influenza confirmed in the community.<h4>Setting</h4>Primary care.<h4>Participants</h4>24,535 patients aged over 75 years from 73 general practices in Great Britain.<h4>Main outcome measure</h4>Death.<h4>Results</h4>In unvaccinated members of the cohort daily all cause mortality was strongly associated with an i ...[more]

PMID: 15313884

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Project description:ObjectiveTo investigate the impact on mortality due to pneumonia or influenza of the change from risk-based to age group-based targeting of the elderly for yearly influenza vaccination in England and Wales.DesignExcess mortality estimated using time series of deaths registered to pneumonia or influenza, accounting for seasonality, trend and artefacts. Non-excess mortality plotted as proxy for long-term trend in mortality.SettingEngland and Wales.ParticipantsPersons aged 65-74 and 75+ years whose deaths were registered to underlying pneumonia or influenza between 1975/1976 and 2004/2005.Outcome measuresMultiplicative effect on average excess pneumonia and influenza deaths each winter in the 4-6 winters since age group-based targeting of vaccination was introduced (in persons aged 75+ years from 1998/1999; in persons aged 65+ years from 2000/2001), estimated using multivariable regression adjusted for temperature, antigenic drift and vaccine mismatch, and stratified by dominant circulating influenza subtype. Trend in baseline weekly pneumonia and influenza death rates.ResultsThere is a suggestion of lower average excess mortality in the six winters after age group-based targeting began compared to before, but the CI for the 65-74 years age group includes no difference. Trend in baseline pneumonia and influenza mortality shows an apparent downward turning point around 2000 for the 65-74 years age group and from the mid-1990s in the 75+ years age group.ConclusionsThere is weakly supportive evidence that the marked increases in vaccine coverage accompanying the switch from risk-based to age group-based targeting of the elderly for yearly influenza vaccination in England and Wales were associated with lower levels of pneumonia and influenza mortality in older people in the first 6 years after age group-based targeting began. The possible impact of these policy changes is observed as weak evidence for lower average excess mortality as well as a turning point in baseline mortality coincident with the changes.

Project description:Background: Vaccination against COVID-19 in Brazil started in January 2021, with health workers and the elderly as the priority groups. We assessed whether there was an impact of vaccinations on the mortality of elderly individuals in a context of wide transmission of the SARS-CoV-2 gamma (P.1) variant. Methods: By May 15, 2021, 238,414 COVID-19 deaths had been reported to the Brazilian Mortality Information System. Denominators for mortality rates were calculated by correcting population estimates for all-cause deaths reported in 2020. Proportionate mortality at ages 70-79 and 80+ years relative to deaths at all ages were calculated for deaths due to COVID-19 and to other causes, as were COVID-19 mortality rate ratios relative to individuals aged 0-69 years. Vaccine coverage data were obtained from the Ministry of Health. All results were tabulated by epidemiological weeks 1-19, 2021. Findings: The proportion of all COVID-19 deaths at ages 80+ years was over 25% in weeks 1-6 and declined rapidly to 12.4% in week 19, whereas proportionate COVID-19 mortality for individuals aged 70-79 years started to decline by week 15. Trends in proportionate mortality due to other causes remained stable. Mortality rates were over 13 times higher in the 80+ years age group compared to that of 0-69 year olds up to week 6, and declined to 5.0 times in week 19. Vaccination coverage (first dose) of 90% was reached by week 9 for individuals aged 80+ years and by week 13 for those aged 70-79 years. Coronavac accounted for 65.4% and AstraZeneca for 29.8% of all doses administered in weeks 1-4, compared to 36.5% and 53.3% in weeks 15-19, respectively. Interpretation: Rapid scaling up of vaccination coverage among elderly Brazilians was associated with important declines in relative mortality compared to younger individuals, in a setting where the gamma variant predominates. Had mortality rates among the elderly remained proportionate to what was observed up to week 6, an estimated additional 43,802 COVID-related deaths would have been expected up to week 19. Funding: CGV and AJDB are funded by the Todos pela Saúde (São Paulo, Brazil) initiative.

Dataset Information

Effect of influenza vaccination on excess deaths occurring during periods of high circulation of influenza: cohort study in elderly people.

Objective

Design

Setting

Participants

Main outcome measure

Results

Conclusions

Publications

Effect of influenza vaccination on excess deaths occurring during periods of high circulation of influenza: cohort study in elderly people.

Similar Datasets

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