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[COMMENTARY] Targeting Vaccines by Zip Code Is the Best Strategy

Over 331 million COVID vaccines have been administered in the United States but, despite this progress, disparities in COVID vaccination persist. They may even stand to get worse since all adults in the United States will be eligible for vaccines as of April 19 — just as infections from variants start to rise.

We’re not ready to delimit vaccine distribution just yet.  Compared with their share of case and death rates with their demographic proportions by state, Black and Hispanic people remain under-vaccinated in every state for which we have data. In contrast, vaccination rates for white people are almost two times higher than those for Black and Hispanic individuals. Somehow states keep missing the mark.

The reason for this is they aren’t aiming properly. The best way to cure the inequity is geographic targeting of vaccines by ZIP Code, like Montgomery County, MD, Milwaukee County, WI, Illinois and Arizona and parts of Rhode Island have already started to do.  Geo-targeting would have achieved the same beneficial results in the initial vaccine rollout and would have avoided at least some dicier political considerations. For instance, distribution by zip code would have prioritized nursing homes as most states did but provided political cover to include prisons, whose zip codes would have attracted vaccines for having an infection rate five times that of the general public.

Allocating geographically naturally addresses the inequities we’re witnessing. North Carolina was the first state to tinker with vaccine distribution. The state changed vaccine allocation to address disparities by giving more vaccines to counties with higher numbers of historically marginalized populations. Vaccine providers are also expected to provide a percentage of vaccines to minority populations that equals or exceeds the demographic makeup of their area. That is, if a county is 33% Black, then at least 33% of vaccines must be administered to Black recipients. And if they don’t, the state will take back their vaccine supply.

The District of Columbia, where communities hardest hit are the least likely to be vaccinated, is prioritizing vaccine appointments by ZIP code so that areas, where people are disproportionately impacted, have access to the vaccines first.

Zipcode targeting looks to be the best way to avoid distribution inequities. Los Angeles Mayor Eric Garcetti has admitted as much, that targeting by zip code would have saved lives. California  When Garcetti said this, Gov. Gavin Newsom had already pledged that 40% of vaccines would go to the hardest-hit zip codes but Garcetti seemed to imply that that was too little, too late.

Logic suggests that distributing according to location makes sense; COVID is a disease of proximity – hence the social distancing guidelines that have persisted since last year.  Basically, because the spread of COVID  infection is geographically asymmetrical, the solution must be similarly spatially lopsided.

But empirical evidence lends credence to distributing vaccines by geography, too.  One study from Ontario found that prioritization of COVID vaccine distribution by both age and neighborhood, instead of just age alone as some states are doing, would result in a 10 to 20 percent greater reduction in cases, hospitalizations, and deaths from the virus. It makes sense; both deaths and hospitalizations are strongly associated with both age and neighborhood — if you are older or you live in an area with a higher rate of COVID infections, you’re more likely to get sick.

And this isn’t just true for COVID — studies of vaccines for other conditions also show geographic prioritization works. During the 2009-10 H1N1 flu pandemic, Arizona prioritized vaccines for the 2009-2010 H1N1 flu pandemic by counties and state health authorities reduced the overall attack rate of the virus. In another study, biostatisticians concluded an optimal vaccine allocation strategy needs to include geographic prioritization, especially when regional differences persist, as they do for COVID. Malaria control and even HIV control strategy within the United States has embraced geographic or “hotspot” prioritization. Yet for COVID-19, targeting like this is an exception, not a rule.

Simply allocating vaccines by parameters such as age — but excluding geography — could result in wealthier areas, with lower cases and deaths, receiving care, and the most COVID-infected areas, which are often communities of color, being left out. This is exactly what we’re seeing: the ZIP codes with the highest deaths, who also have poor and minority populations, have low vaccination rates. That was the problem with initial distribution plans; they assumed that only age or co-morbidity were the risk factors that deserved the most attention.

Geographic targeting isn’t a failsafe. In Washington DC, the wards with the highest COVID infection rates are still the least vaccinated. But zip code prioritization is still relatively new there and elsewhere. As Mayor Garcetti said, if health officials had started distribution according to zip code way back in December, we might be in a very different place now.

And that begs the question of why we didn’t start that way. After all, the United States relies on geographic data collected in the Census for much of its federal policy. Technically, they’re called “Zip Code Tabulation Areas” instead of Zip Codes because “Zip Code” is trademarked by the United States Postal Service, but they are reliable indicators of income distribution. Targeting by zip code gets really close to prioritizing under-resourced communities over wealthier ones in an explicit way, something that state policymakers seem to try to avoid.

Indeed, with the eligibility categories, people with more money and less infection risk have been able to squeeze their way in. Zipcode prioritization might not have made it harder for them, but it would have made it easier for the people who need vaccines more.

Municipalities, as opposed to states, seem to be the best at collecting data by zip code; Chicago and New York have made their zip code data available to the public. And some states like Virginia don’t have zip codes for all data cases. But they have enough and we can’t let perfect antagonize the good, especially when the United States, even with 40% of adults partially vaccinated, is far from the best in distribution; other countries have done much better.

In fact, this is the exact change we need at this moment: per guidelines by the CDC and the National Academies, the next step after vaccinating the highest-risk people should be to incorporate place-based disparities and provide vaccines to harder hit and historically marginalized communities. This is the right thing to do, practically and ethically.

With more vaccines coming in many states against the backdrop of a fourth surge, now is the time to ensure that vaccine equity is finally addressed.  Existing approaches until now have only perpetuated disparities by race, place, and class. Geographic targeting is the way to address inequities. We cannot throw away this shot.

About the Author

Sudhakar V. Nuti is an internal medicine/primary care resident doctor at Massachusetts General Hospital and MGH Chelsea Healthcare Center and is a Public Voices Fellow with the Op-Ed Project.



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