Area-based vaccination would better protect against COVID-19
Dr Ruth Watkinson and Professor Matt Sutton, from the Health Organisation, Policy and Economics (HOPE) group and the Institute for Health Policy and Organisation, argue that everyone living in areas with the highest coronavirus infection rates should now be prioritised for vaccination.
Lessons from Phase 1
The Joint Committee on Vaccination and Immunisation (JCVI) phase 1 vaccination goals were to ‘save lives and protect the NHS’, with prioritisation determined by individual risk of severe COVID-19. Other than health and social care workers, prioritisation was determined by age group and health conditions. However, two layers make up the overall risk of severe COVID-19 – firstly the risk of coronavirus infection, and secondly the risk of severe COVID-19 if infected.
Phase 1 prioritisation focused exclusively on the second layer of risk, divorced from the context of peoples’ lives such as social deprivation, ability to work from home, or geographical region. Yet, all these factors affect the first layer of risk: the risk of coronavirus infection.
For example, a healthy person in their mid-70s (priority group 3) getting supermarket deliveries in an area with low case rates faces a low overall risk of severe COVID-19 because they have almost no exposure to coronavirus. However, they were prioritised far ahead of a 64-year-old (priority group 7) supermarket worker in an area with high case rates, who faces high overall risk due to far-greater risk of infection coupled with moderate age-based risk of severe COVID-19.
Following new modelling incorporating ethnicity and postcode, some additional people have been advised to shield and will now be prioritised for vaccination. While this is welcome news, it also tacitly acknowledges the health inequalities generated by fundamental flaws in the original strategy. Sadly, even this meagre progress towards equality has been reversed for phase 2, with eligibility determined exclusively by age.
Phase 2 priorities
The JCVI estimates those eligible for vaccination in phase 1 account for 99% of preventable mortality due to COVID-19. So, while we should guard against any avoidable deaths, we must balance protection from a rare event against other harms and inequalities. We now know the vaccines protect against infection as well as severe disease, so we argue that prioritisation based on the risk of coronavirus infection (not severe disease risk) would be more equitable and more efficient for four reasons:
Firstly, long COVID is an often-debilitating illness that affects many, including those with only mild initial COVID-19. A recent US study found almost 1 in 3 reported persistent symptoms and worse health-related quality of life 6 months after mild COVID-19. Similarly, UK estimates indicate long COVID is common, including amongst children. Importantly, there is no clear association between age and long COVID - the only known risk factor is coronavirus infection.
Secondly, vaccination ‘need’ can be considered more broadly, given the high costs and wide inequalities associated with lost earnings or education due to self-isolation. For example, last autumn term there were wide geographical and socioeconomic inequalities in in-person school time, with children in areas with higher case rates more frequently sent home to self-isolate.
Thirdly, prioritising those with the highest infection risk has societal benefits. Although the vast majority at high risk of COVID-19 mortality will have been vaccinated in phase 1, neither uptake nor vaccine effectiveness are 100%. Nationally, even 95% uptake and 95% efficacy would leave several million people highly vulnerable, risking another surge in deaths as restrictions are eased. Allocating phase 2 vaccinations to those with the highest infection risk first would reduce onward transmission, providing a secondary ‘shield’ to those still at risk. More broadly, vaccination can help drive down infection rates, and targeting areas with persistently higher rates would be the most efficient use of limited supplies.
Finally, targeting vaccines to those with higher infection risk would reduce the opportunities for the emergence of additional variant strains. The risk of variants that evade the protection from current vaccines is a global threat to the longevity of vaccination success, and every additional infection increases the probability of this occurring.
Practical implications for phase 2 strategy
So, how can we practically allocate vaccines to those at highest risk of infection? While many factors play a role, the single biggest predictor is the number of positive COVID-19 cases in each local area at any given time. Although the current national lockdown is reducing new cases, reductions are not shared equally across the country. The latest REACT study data shows that while cases in the South East and London fell by over 80%, rates only fell by 24% in Yorkshire and the Humber, and rates remain particularly high across the North. This mirrors the regional trends last year, when Northern regions suffered higher infection rates, despite sustained damaging local restrictions.
Several leaked official reports concluded rates are - and will likely continue to be - stubbornly high in deprived areas, due to a ‘perfect storm’ of many people in jobs that cannot be done from home, overcrowding, unmet financial needs, and failures of the Test and Trace system. At the time of the leak, Bolton was the worst-affected area with a rate of 98.1 coronavirus cases per 100,000 while Southampton had a rate of just 3.2. It is therefore unreasonable to suggest 20-, 30-, or 40-year-olds across the country face equivalent risks from coronavirus, with geographical differences dwarfing age-based differences in hospitalisation (3-fold increase per decade). Instead, it would be far more equitable to prioritise local areas with the highest case rates, and where ‘R’ – the spread of cases – is highest. This is entirely feasible with close-to-real-time data available from REACT and daily testing figures.
Importantly, this approach would increase access to vaccination for those from ethnic minority groups, who have suffered disproportionate impacts from the pandemic. Systemic racism has put people from ethnic minority groups at higher risk for a range of reasons, from being more likely to have jobs with higher exposure and feeling less able to raise safety concerns at work, to being more likely to live in neighbourhoods with higher case rates. While other risks stemming from racism are complex to address, prioritising areas with highest infection rates is a straightforward way to increase prioritisation of many people from ethnic minority backgrounds.
Perhaps most importantly, prioritising protection against coronavirus infection risk is not at odds with the goal of protecting against the rarer but serious outcome of severe COVID-19 amongst the under 50s. In reality, these goals align, because the overall risk of severe COVID-19 is so highly dependent on who is the most exposed to infection, particularly as national case rates fall and inequalities in local rates become increasingly stark.
