The effects of the first national lockdown in England on geographical inequalities in the evolution of COVID-19 case rates: An ecological study

BackgroundSocio-economic inequalities in COVID-19 case rates have been noted worldwide. Previous studieshave compared case rates over set phases. There has been no analysis of how inequalities in cases changed overtime and were shaped by national mitigation strategies (e.g. lock downs). This paper provides the first analysis of the evolution of area-level inequalities in COVID-19 cases by deprivation levels in the first wave of the pandemic (January to July 2020) in England - with a focus on the effects of the first national lockdown (March - July 2020). MethodsWeekly case rates per Middle Super Output Area (MSOA, n=4412) in England from 2020-03-15 to 2020-07-04 were obtained, and characteristics of local epidemics were calculated, e.g. the highest case rate per area. Simple linear and logistic regression analyses were employed to assess the association of these metrics with index of multiple deprivation (IMD). Local authority-level (n=309) cases were used similarly in a sensitivity analysis, as these data were available daily and extended further back in time. The impact of lockdown was assessed by comparing the cumulative case rate in the most deprived 20% of MSOAs to the least deprived 20%, for the periods before the lockdown, and by the end of lockdown. FindingsLess deprived areas began recording COVID-19 cases earlier than more deprived areas and were more likely to have peaked by March 2020. More deprived areas case rates grew faster and peaked higher than less deprived areas. During the first national lockdown in the UK, the relative excess in case rates in the most deprived areas increased to 130% of that of the least deprived ones. InterpretationThe pattern of disease spread in England confirm the hypothesis that initial cases of a novel infectious disease are likely to occur in more affluent communities, but more deprived areas will overtake them once national mitigation strategies begin, and bear the brunt of the total case load. The strict first national lockdown served to increase case rate inequalities in England. FundingThis work was supported by a grant from The Health Foundation (Ref: 2211473), who took no part in the design, analysis or writing of this study. Research in Context Evidence before this studyThe magnitude and distribution of deprivation-related inequalities in COVID-19 cases have been reported for England and many other countries, however, none have yet investigated the initial evolution of these inequalities, nor the effects of the first national lockdown. Added value of this studyWe leverage the benefits of two separate datasets of COVID-19 case counts to investigate the initiation and evolution in inequalities in disease burden by deprivation. We found that cases were first recorded in less deprived areas before rising faster in more deprived areas. The first national lockdown led to an increase in these geographical inequalities. Implications of all the available evidenceNational lockdowns are an important tool in the armoury of pandemic control, but their timing and duration must be carefully decided and be locally specific. Because case rate inequalities were already present before lockdown in England, movement restrictions served to further increase them. Summary Box Section 1: What is already known on this subjectGeographical inequalities in COVID-19 case rates have been noted worldwide, and in England. However, how these inequalities were affected by policy responses - such as national lockdowns - has yet to be investigated. Section 2: What this study addsWe examined geographical inequalities in COVID-19 case rates by deprivation during the first English lock down (March - July, 2020). We find that cases were first reported in the less deprived areas of England, but this pattern quickly reversed and large excesses of cases occurred in the most deprived areas during the first national lockdown. Case rates in more deprived areas also rose more sharply, peaked higher, and then dropped faster than in less deprived areas. Inequality in cumulative case rates grew over the lockdown, increasing inequalities in disease burden.