An investigation into ethnic group and deprivation inequalities in influenza and COVID-19 hospitalizations, post-pandemic
This study of England's 2023–2024 data reveals that while ethnic disparities in influenza hospitalizations persist (particularly for Pakistani and Bangladeshi groups) and are partially driven by deprivation, vaccination uptake and deprivation significantly mediate inequalities for both influenza and COVID-19, underscoring the need to prioritize improving vaccination coverage in under-vaccinated populations.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of a preprint that has not been peer-reviewed. It is not medical advice. Do not make health decisions based on this content. Read full disclaimer
Every year, seasonal viruses like influenza and the virus that causes COVID-19 sweep through communities, causing illness that ranges from a mild cough to a life-threatening condition requiring hospital care. While these infections affect everyone, they do not hit all groups of people with the same force. Some communities end up in hospitals far more often than others, a pattern that health officials call inequality. To fix these unfair gaps, leaders need to understand not just that the gap exists, but why it exists. Is it because certain groups are sicker to begin with? Is it because they live in areas with fewer resources? Or is it because they are less likely to receive protective vaccines? Answering these questions is difficult because these factors are tangled together; poverty often leads to worse health, and both poverty and poor health can make it harder to get vaccinated. Without untangling these threads, it is impossible to know which levers to pull to make things better.
A team of researchers at the UK Health Security Agency set out to untangle these threads for England during the winter of 2023 and 2024. They focused on people who were eligible for vaccines against both flu and COVID-19, a group that includes older adults and those with long-term health conditions. By linking vast amounts of data on who got sick, who got vaccinated, where they lived, and what health conditions they had, the scientists built a clear picture of how these factors interact. Their goal was to see how much of the difference in hospitalization rates between ethnic groups and between rich and poor areas could be explained by specific, changeable causes like vaccination rates or underlying health issues.
The study revealed a striking difference between the two viruses. For influenza, the gap in hospitalization rates was wide and persistent. People from Pakistani and Bangladeshi backgrounds were significantly more likely to be hospitalized for the flu compared to White British individuals. The researchers found that the most deprived areas, those with the lowest income and highest unemployment, also saw much higher hospitalization rates. When they looked closely at why these gaps existed, they discovered that where a person lived played a major role. For people from Pakistani and Bangladeshi backgrounds, the fact that they were more likely to live in deprived areas explained about a quarter to two-fifths of their higher risk of hospitalization. This means that the economic conditions of their neighborhoods were a powerful driver of their health outcomes.
However, the story was different for COVID-19. In this post-pandemic period, the researchers found almost no difference in hospitalization rates between ethnic groups. While some groups had slightly lower rates than the White British population, no group had a disproportionately higher risk. This was a notable shift from the early years of the pandemic, when ethnic minority groups faced much higher risks. The researchers suggest this change may be because these communities had already built up strong immunity through previous infections, leveling the playing field for severe outcomes. For COVID-19, the only clear inequality remained tied to poverty, with the most deprived areas still seeing higher hospitalization rates than the least deprived.
The researchers then asked what was driving these inequalities. They tested whether having more health conditions, known as comorbidities, explained the differences. Surprisingly, within the group of people eligible for vaccines, having these conditions did not explain why some groups were hospitalized more often than others. This is likely because the vaccine program itself already targets people with these conditions, effectively shielding them from the worst outcomes. Instead, the key factor that explained the inequalities was vaccination. For both flu and COVID-19, people in the most deprived areas were less likely to have been vaccinated. This lower vaccination rate accounted for a significant portion of the extra hospitalizations seen in poor areas. For the flu, the gap in vaccination explained between 17 and 26 percent of the extra risk for the most deprived groups. For COVID-19, once the researchers accounted for vaccination and health conditions, the inequality between rich and poor areas essentially disappeared.
This finding points to a clear path forward. The study suggests that while deep-seated issues like poverty and the conditions it creates are hard to fix quickly, vaccination is a tool that can be improved right now. The data shows that if vaccination rates were raised to match those in wealthier areas and among White British populations, the number of hospitalizations would drop significantly, and the unfair gaps would narrow. The researchers emphasize that while tackling poverty is essential for long-term health, improving how vaccines are delivered to under-vaccinated communities is an immediate and actionable priority. By focusing on these missed opportunities for protection, health officials can make a real difference in who ends up in the hospital and who stays safe at home.
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