This is the second in a series on opening up safely with the goal to provide a framework for evaluating risk as states and counties begin to relax stay home orders. We first discussed How to Assess Your Risk for Severe COVID-19 Infection, an important step in determining what’s best for you and your health. Today, we look at assessing how safe your county is, and in subsequent posts, we’ll evaluate specific activities and ways to mitigate your risk of exposure.
We outlined in our first post, why it’s important to know your risk for developing a severe case of COVID-19 before you participate in an activity. Another factor for determining how to proceed is to have an understanding of the safety of your county. The risk of infection and level of preparedness varies widely on the county and state level, so it’s important to consider how your local area is doing before moving forward. To understand the prevalence of COVID-19 and how strained a community’s health care system may be, we look at three main indicators: infection rate, positive test rate and ICU headroom used.
Infection rate or in epidemiology, the basic reproduction number R0, quantifies the disease’s virality. This rate represents the expected number of new cases that will be generated by each person who has the infection. If R0 is 4, it means that for each person who gets the disease, they on average will spread it to 4 people. The greater the infection rate, the harder it is to control the spread.
What to look for: If the infection rate is under 1, the cases are trending down. If the infection rate is over 1, it means the infection is still spreading and higher levels of precaution are advised.
Positive Test Rate
Positive test rate is the percentage of tests in the county that were positive over a period of time. This is being used by public health authorities as a proxy for testing capacity. The logic is that if adequate testing is in place, the percent of tests that are positive should be low. It’s important to note that this doesn’t actually measure the tests available based on the population of the county. It is overall still a good metric to look for, as a lower positive rate can indicate both adequate testing capability and few COVID-19 cases.
What to look for: The WHO recommends a positive test rate under 10% based on the experience of countries that have been successful in containing the virus. Above 10% can indicate an outbreak of infection or inadequate testing capacity.
ICU Headroom Used
ICU headroom used indicates the percentage of ICU beds that are currently occupied. This is an important measurement to understand if your county hospitals will be able to absorb the healthcare demand in the event of a surge of new cases.
What to look for: Recommendations advise that a county should be able to double their current ICU capacity in the event of a COVID-19 outbreak. That means you should be looking for a current ICU capacity under 50%.
You can find all of this data for your county on your county website’s health pages. COVID Act Now and the New York Times are also compiling nationwide information. These are not perfect indicators — some counties are incomplete and some of these metrics just serve as proxies — but they do help to provide a sense of your county risk level. If your county risk is high or critical, even if there aren’t Stay In Place orders, you should strongly consider limiting your exposure. Regardless of your county risk level, we recommend taking precautions like wearing a mask and keeping at least six feet of distance from other people.