In the fight against COVID, data has been one of the most powerful weapons for public health officials. Now, however, more than half a year into the pandemic, it’s become clear that many state governments aren’t collecting critical data related to coronavirus testing. As a result, they may be undercounting total COVID-19 cases.

The lack of data may mean that public health professionals don’t have a full picture of how the virus is spreading. This patchy data could quickly become dangerous as we approach flu season and a potential COVID spike this winter.

How States are Collecting Data and What they May be Missing

Most COVID data in the U.S. comes from labs that process PCR swab coronavirus tests. These tests, while mostly accurate, can take days to be processed at a lab. As a result, many providers are instead turning to much quicker antigen tests, which detect the presence of certain viral antigens produced by COVID and can be processed within an hour or even faster.

They’re also typically much cheaper than PCR tests, which can cost anywhere between $60 and $300 if insurance isn’t willing to provide coverage.

Some of the quickest antibody tests on the market are capable of providing results in just 15 minutes, allowing individuals to know if they’re sick before leaving the testing site and potentially helping them quarantine earlier and reduce the spread of the virus.

However, providers using these antigen tests don’t have an easy way to send their case data to the federal government. While providers are required to send positive and negative test results to local agencies in most states, those numbers aren’t making their way into the official counts.

According to reporting from USA Today, more than 20 states are still not reporting antigen test results, or are excluding antigen-positive tests from official case numbers. These unusual data reporting policies cut across party lines, with both Democratic and Republican state governments — including those in California, Georgia, Illinois, and Tennessee — continuing to not report that data.

As a result, antigen test positives and negatives are being left out of both state and federal numbers.

Researchers fear that this patchy approach to data reporting may give the public the impression that case numbers are falling as testing increases, even if the number of positive antigen test results is actually rising.

Data on COVID-19 Cases May Improve

There are signs that officials at all levels of government are aware of the limitations of the current approach, and actively working to improve data collection on COVID-19 cases.

In the summer, researchers began sounding the alarm on holes in state data sets, which were missing key information on case demographics like age, gender, race, and income. This information is essential for epidemiologists and sociologists studying how the virus was spreading in poor and minority communities, as well as officials who want to see if relief programs have been effective.

In July, the U.S. Department of Health and Human Services announced a new rule that required testing laboratories to report race and ethnicity, along with ZIP code, age, and gender, to the federal government with all COVID-19 test results starting August 1.

Still, despite this new rule, many state databases continue to leave out key information, according to Johns Hopkins University — especially when it comes to testing.

The Future of State-Level COVID Data in the U.S.

As the pandemic continues, data will be essential for officials wishing to manage the virus’s spread. Researchers continue to fear that states aren’t doing enough to ensure robust and comprehensive data sets. While there have been strides to improve COVID-19 case data, patchy state information is likely to cause problems well into the future.