ZIP code data shows big vaccine gap in state

California has struggled to vaccinate its residents equitably throughout the pandemic — so much so that in March, the state began allocating 40% of its vaccine supply to residents in its 446 lowestincome ZIP codes (the state has a total of 1,746).

Yet despite this and other local initiatives, California continues to vaccinate its population unequally, according to data from the California Department of Public Health. The gap in vaccination rates between people living in the state’s healthiest and wealthiest quartile of ZIP codes and those living in the least healthy and poorest ZIP codes continues to grow, leading to a 21 percentage point difference as of late April.

Last week, the health department released detailed data on vaccination rates for every ZIP code in the state. The data includes an estimate of the share of each ZIP code’s 16andolder population that has received at least one dose of COVID19 vaccine, along with a measurement the government calls its Vaccine Equity Metric. That metric divides each ZIP code into quartiles, based on factors like economic stability and health care access. ZIP codes with a ranking of 1 are considered the most vulnerable and lowestincome; ZIP codes with a 4 ranking are considered the wealthiest and least vulnerable.

The Chronicle’s analysis of the data shows that the Bay Area is seeing similar inequities in its vaccination rates as the rest of the state. Only 10 ZIP codes in the Bay Area were among the state’s lowest income and eligible for increased vaccine supply. But while the region has comparably fewer ZIP codes with 1 and 2 vaccine equity rankings, the ZIP codes in those categories are still falling behind the region’s wealthier areas: ZIP codes in the 1st quartile have an average of 43% of their 16andolder residents vaccinated with at least one dose, while ZIP codes in the fourth quartile have an average of 69%.

Across the Bay Area’s 264 ZIP codes with 500plus eligible residents, the 50 ZIP codes with the highest vaccination rates all have vaccine equity scores of 3 or 4. The ZIP code with the lowest vaccination rate, 94535 in Solano County, has a vaccine equity rank of 1. Just under 10% of its eligible residents have been vaccinated with at least one dose, according to the data.

Note on the data: Of the nearly 1500 ZIP codes with more than 500 residents 16 or older, the data shows 25 as having vaccination rates greater than 100%, including nine in the Bay Area. According to state health department, this could be because these ZIP codes’ population estimates are too low, or because people are coming into lowpopulation ZIP codes to get their vaccines and are erroneously reported as living in that ZIP code.

Jessica Christian / The Chronicle 2020 Cenorde Lesly, who works in the kitchen at the Tamalpais Marin assisted living facility in Greenbrae, gets a coronavirus vaccination in December.