The hidden link between COVID and Legionnaires’ disease: poverty

The COVID-19 pandemic has underscored the need to increase investment in the nation’s public health infrastructure. But when we began to examine the pandemic’s ripple effects in our own community of Baltimore, we identified another area in pressing need of investment: healthy housing that keeps under-resourced and marginalized people from getting sick.

Legionnaires’ disease is one of the deadliest waterborne infections in the United States. An estimated 52,000 to 70,000 Americans get Legionnaires’ disease each year. Even so, this illness is something few doctors have seen in practice since it first emerged in 1976.

Indeed, it had been many years since our pulmonary and critical care team at Johns Hopkins Bayview Medical Center had seen a case of Legionnaires’ disease. Then, in 2021, in the midst of the pandemic, we had four cases — three of them since June.

As clinicians and public health practitioners, we wondered what was going on. Although we’ve only begun to investigate the water in and around Baltimore, we quickly determined that our patients have two things in common: poor housing in some of the city’s older neighborhoods and socioeconomic disadvantage. They were, in fact, similar to some of the populations hit hardest by COVID-19.

To us, housing seems the likely point of intersection between these two diseases — specifically, piped drinking water systems in old, neglected buildings.

Legionella bacteria grow in biofilms lining drinking water pipes. They can be inhaled from water droplets emerging from faucets or showers and lead to infections. These bacteria thrive in stagnant water. In old buildings where the pipes have not been well-maintained, Legionella can contaminate entire potable plumbing water systems.

The U.S.’s drinking water infrastructure was not built for shutdowns. When the COVID-19 stay-at-home orders emptied out offices, schools, restaurants and gyms, water that regularly flowed through pipes to downtown areas slowed or stopped. The massive shifts in water demand challenged water utilities to maintain high enough levels of chorine disinfectant throughout municipal drinking water networks. Low chlorine can allow Legionella to replicate in biofilms present in pipes. While many compounding factors contribute to Legionella growth, it is clear that during the COVID-19 lockdown water pipes in older buildings, especially older apartment buildings, became potential hotbeds for Legionella bacteria.

There are no laws requiring building managers to update their pipes, which is exorbitantly expensive to do. The Safe Drinking Water Act does not directly regulate Legionella bacteria in U.S. drinking water distribution systems, and data on their presence are lacking. Meanwhile, public health departments are ill-equipped to undertake environmental investigations when sporadic cases are reported, and utility companies are not responsible for water quality on private property.

In the end, the same people who have been disproportionately affected by the pandemic — those with low incomes and few resources — are also the most susceptible to Legionella. They live in communities with aging water infrastructures that have a greater likelihood for Legionella in their homes and have fewer resources to spend on costly water testing and filtration systems.

There is an ethical duty to protect vulnerable communities, especially in response to the compounding devastation that infections causing COVID-19 and Legionnaires’ disease pose. That includes ensuring that the homes in which people live — and in which they may be relegated to quarantine or isolate — are not poisoning them.

The public health community needs to go outside the box to help ensure healthy drinking water. At the federal level, the Centers for Disease Control and Prevention needs to provide clear guidance to local health departments and building managers for addressing Legionella and offer technical expertise and financial resources. Local health departments should form units that conduct publicly-funded in-home water assessments for people diagnosed with Legionnaires’ disease.

In addition, a federal task force is needed to make recommendations for managing biofilm-based pathogens so that communities can expect clean, healthy water from their taps.

Health care professionals who work with people diagnosed with Legionnaires’ disease should talk with them about their housing situations and relay their findings to local health departments, which then can instruct affected individuals on the next steps. This type of referral is similar to what a clinician would do for patients with common non-communicable diseases like diabetes, referring them to community services to assist in the management of the disease.

Such actions will help ensure that marginalized people who often reside in poor housing will not suffer one public health crisis after another — and demonstrate that public health is a public trust for all.

Panagis Galiatsatos is a pulmonary and critical care physician and assistant professor in the Division of Pulmonary Medicine and Critical Care at Johns Hopkins School of Medicine. Natalie Exum is an environmental health scientist in the Department of Environmental Health and Engineering at the Johns Hopkins Bloomberg School of Public Health. Kellogg Schwab is a professor of water and public health in the Department of Environmental Health and Engineering at the Johns Hopkins Bloomberg School of Public Health and Whiting School of Engineering.