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This Data Would Help San Diegans Better Understand Local Coronavirus Cases

San Diego County’s Health and Human Services Agency / Photo by Adriana Heldiz

Various San Diego media outlets have been reporting data on the COVID-19 health disaster based on information provided by the county of San Diego. While the data appears to be accurate, the manner in which it is reported, both by the county and the media, often fails to provide a meaningful barometer of daily outcomes.

One key data point that is commonly used is positive tests, which are typically reported as a cumulative number (since Feb. 14, 2020). The tests, however, have been limited in number and are not administered randomly to the general population. As tests become more widely available, the number of positive tests would be expected to grow, even if the number or percent of infected people were to stay the same. So reporting cumulative positive tests offers little insight into the course of the virus.

Another option might be to report on the percent of tests that are positive. This, though, would not factor in the variable that tests are hopefully prioritized for those who believe, or whose doctors believe, they may be infected. Thus, unlike a random sampling of the population, the percent of positives is almost certainly artificially high relative to the infection rate of the general population.

There are three data points that would seem to be objective and useful: hospitalizations, intensive care admissions and deaths. The county reports on these, but their reporting seems to be primarily focused on the day-to-day change and cumulative numbers, just as is the case for reports of positive testing.

What would be more instructive, on the part of both the county and the media, would be to extract this same data and to provide a graphical representation of the long-term variations on a day-to-day basis. For example, over time are the number of hospital admissions rising or falling from day to day? At what rate? A graph like the one below, if published by the county and the media and updated daily, will better inform the public than the focus on yesterday’s numbers and the cumulative totals.

There is a second set of data points the media should be asking the county to divulge, which it is not presently doing: the number people currently hospitalized and in intensive care. Presumably, some hospitalizations and intensive care cases are resulting in recovery and discharge from the hospital, but the county is only reporting the total numbers that have been hospitalized since the start of the emergency, as if none are ever resolved. Since a major concern is that hospitals could be overwhelmed, the county should report each day on the current hospitalized patient loads and how these are varying over time. This could help encourage the public to maintain social distancing, for example.

In the absence of widespread, random testing and follow-up, we will perhaps never know what percent of the population contracted the virus and survived, versus those who died. What can be reliably reported, in the here and now, is the fluctuations in hospitalization admissions, intensive care admissions and deaths, to give us some sense whether these are rising or falling. This will give us a meaningful sense of the course of the pandemic locally and how our efforts to stem the tide are working.

B. Chris Brewster, a San Diego resident, is president of the Americas region of the International Life Saving Federation and editor of American Lifeguard Magazine.