Contact tracing is when individuals who have had interaction with an infected person are notified and asked to self-isolate. This is an essential instrument in keeping the highly infectious COVID-19 from spreading further. As states are starting to reopen, you would think that they would have this set up in order to protect the public. However, most areas don’t have the necessary teams in place to do this either at all or to the level that public health experts say that is needed.

For some areas, they’re lacking funding to increase their contact tracing capacity. This is true despite since March, Congress has provided $631 million to state and local health departments for surveillance, which is supposed to include contact tracing. However, according to an estimate by the Association of State and Territorial Health Officials and the Johns Hopkins Center for Health Security, the amount that is considered necessary to actually do the job is $3.6 billion.

Others areas are having difficulty reaching the people that they need to inform. In some areas where contact tracers try to reach people, many recipients didn’t answer their phones. This raises concerns about how effective contact tracing can be when the public doesn’t cooperate. Another issue is that as the number of cases continue to spike rapidly, it’s hard for contact tracers to reach everyone that is on their list.

This inability to warn people is worrisome especially because a study published in The Lancet Global Health found that the number of deaths worldwide has disproportionately affected the most vulnerable people—those with underlying health conditions, such as diabetes and diseases that impact the heart and lungs. Unfortunately, 22% of the global population, or 1.7 billion people, fall into this category. Healthy older individuals aren’t included in this number, even though they’re at a higher risk due to their age. The number also doesn’t take into account risk factors, such as poverty and obesity. These can affect a person’s vulnerability to disease and access to treatment.

The researchers collected their data from the Global Burden of Disease Study, which is a comprehensive worldwide epidemiological survey that was last updated in 2017. They used the information to identify the number of individuals worldwide with at least one of the high-risk conditions. There were almost 200 countries included in the study. The analysis found that more than one-fifth of the world’s population may be at increased risk for developing a more severe form of the disease. The researchers did point out that increased risk is not equivalent to high risk, which only refers to a small subset of patients. The study also determined that about 4% of the world’s population (close to 349 million people) would require hospitalization if they became infected.