Is a new COVID-19 surge primarily hurting Kansas counties with low vaccination rates? Here’s what the data says.
Many Kansas counties with lower vaccination rates appear to be hurting more than counties with higher vaccination rates amid the new surge in COVID-19 cases fueled by the delta variant.
The latest data on COVID-19 cases and vaccination rates in the 105 Kansas counties show a weak correlation, according to a Topeka Capital-Journal analysis of statistics from the Kansas Department of Health and Environment and White House COVID-19 Task Force.
Phillip Steiner, a Kansas Health Institute analyst with a master’s degree in economics, replicated the analysis at The Capital-Journal's request and found similar results.
During a July 16 media briefing of the White House pandemic task force, Centers for Disease Control and Prevention director Rochelle Walensky noted a nationwide trend. Counties that have "high" or "substantial" community transmission "most frequently correspond to counties with low vaccination rates," she said.
"I still think it’s too soon to tell in Kansas whether that’s the case," Steiner said of Walensky’s comment. "Now, there are counties with lower (vaccination) rates that have high cases per 100,000, but there are also plenty that have zero."
Jeff Zients, the White House COVID coordinator, doubled down on the comments during a Thursday news briefing.
"The data is clear: The case increases are concentrated in communities with low vaccination rates," Zients said. "In fact, the counties with the highest case rates have significantly lower vaccination rates than counties with lower case rates."
There are plenty of Kansas examples to support the claims from the White House. The worst case rates so far this month are in Cherokee, Crawford, Bourbon and Doniphan counties. Those four counties had less than 34% of their population fully vaccinated at the start of the month, below the statewide vaccination average.
But there are other instances of counties with low case rates and comparatively low vaccination rates, such as Meade, Rawlins and Decatur counties, which were also below 34% as of July 1. In fact, none of those counties have recorded a single case this month, according to KDHE data.
"We don’t have enough data points or enough time yet to know that there’s a strong relationship between vaccination rates (and case rates),” Steiner said. “Conceptually, that makes total sense. That’s how it should work. We’re expecting it to work like that. We don’t necessarily have data in Kansas showing that yet, or at least not with the level of statistical certainty we would like to see.”
See Kansas data county by county
The Capital-Journal's analysis found a weak correlation between vaccination rates and COVID-19 case rates. In general, the higher the vaccination rate, the lower the case rate.
The computer-generated scatter plot trend line hits zero cases at a vaccination rate above 75%.
Public health experts have estimated that herd immunity could likely be reached somewhere between 70% and 85%.
"We definitely need to watch this kind of weak correlation that you found and see if that grows stronger over time and continues to provide evidence for a higher vaccination rate reducing the case count," Steiner said.
A month ago, the Washington Post in a similar study found that states with higher vaccination rates had fewer coronavirus cases. As of the June 14 story, Kansas had fewer vaccinations and more cases than the national average.
The Capital-Journal's analysis measured the rate of new cases per 100,000 people between June 30 and July 23, using KDHE case and population statistics, for each county. Vaccination rates are the percentage of population fully vaccinated as of July 1, as reported by the White House/CDC.
In statistics jargon, it is unclear whether the numbers are signal or noise, Steiner said. The R-squared value is weak at 2.1%.
Tracking the data is valuable information, Steiner said, but he cautioned that the analysis doesn't account for many other variables that drive case rates. Additionally, the weak relationship means conclusions can't be made with statistical certainty.
Among the many variables are the amount of delta variant, the age of a county's population, socioeconomic status, disparities between ZIP codes, access to health care and proximity to Missouri.
"We just need to wait, and we need to know more about what the delta variant is doing and how that’s impacting cases in Kansas," Steiner said. "Our percentage of delta variant is higher I think than some places. That would definitely have an impact on at what rate you need to be vaccinated to reduce your case count."
Friday's KDHE data showed the highly-contagious delta variant accounted for 98% of COVID-19 cases that underwent genomic sequencing during the week ending July 17.
Kansas hospitals in trouble
While statisticians may be accustomed to waiting for clean, accurate data and accounting for multiple variables before drawing conclusions, doctors and nurses treating COVID-19 patients don't have that luxury.
Steve Stites, the chief medical officer at The University of Kansas Health System, sounded the alarm on the COVID-19 surge during multiple media briefings in the past week. He attributed the new wave to three main variables: the delta variant, the low vaccination rate and the loss of public health mandates.
"We’re in trouble," Stites said. "The numbers are rising. Hospitals are full. We’re turning away patients from outside places who need our care, both with COVID and without COVID. I think we’re at a tipping point, and if we don’t take it seriously, we could easily end up back where we were in November."
Vaccine hesitancy has decreased over time, according to a Kansas Health Institute publication from June using survey data from April. At the end of April, about 15% of Kansas adults said they were undecided about getting vaccinated.
The percentage of respondents who said they definitely won't get a vaccine has remained consistent, at about 8%.
The leading reasons for the undecided adults were concerns about possible side effects, a desire to "wait and see" and a belief that other people needed vaccines more. Widespread distrust of the government and of the vaccines were key reasons among people who outright refuse to get vaccinated.
Stites called on people to get vaccinated and start wearing face masks again. He hinted that chief medical officers from hospitals in the Kansas City area will publicly call for reinstating mask mandates.
"The delta virus is spreading, more people are getting sick and this has become now the pandemic of the unvaccinated," he said. "This situation could well grow worse if we don’t respond."