An unsuspected case of COVID-19 — hospitalized as the pandemic was beginning in the United States — exposed 43 healthcare workers (HCWs) and caused what are thought to be the first occupational infections with the virus, the Centers for Disease Control and Prevention (CDC) reports.1
On Feb. 26, 2020, the first U.S. case of community-acquired COVID-19 was confirmed in a patient at “hospital B” in Solano County, CA. The patient initially had been evaluated at a different facility, “hospital A,” the CDC says.
“At that time, COVID-19 was not suspected, as the patient denied travel or contact with symptomatic persons,” the CDC reports. “During a four-day hospitalization, the patient was managed with standard precautions and underwent multiple aerosol-generating procedures, including nebulizer treatments, bilevel positive airway pressure ventilation, endotracheal intubation, and bronchoscopy.”
Several days later, the patient tested positive for SARS-CoV-2, the pandemic virus that causes COVID-19.
“Among 121 hospital A healthcare personnel (HCP) who were exposed to the patient, 43 (35.5%) developed symptoms during the 14 days after exposure and were tested for SARS-CoV-2,” the CDC notes. “Three had positive test results and were among the first known cases of probable occupational transmission of SARS-CoV-2 to HCP in the United States.”
Other HCWs could have been infected with the virus but were not picked up in the testing, the CDC acknowledged. Serologic testing was not done, with the workers tested through nasopharyngeal and oropharyngeal specimens. Likewise, additional infections might have occurred among asymptomatic exposed HCP who were not tested.
“It is possible that additional infections may have occurred among the 40 symptomatic healthcare personnel who tested negative, due to potential limitations in test sensitivity and timing,” says lead author Amy Heinzerling, MD, an officer in the CDC Epidemic Intelligence Service. “It is also possible that their symptoms were caused by other respiratory infections or by noninfectious causes, such as seasonal allergies. Most of these 40 healthcare personnel had mild symptoms and none required hospitalization.”
The three infected staff members performed more physical examinations of the patient and had longer exposures during nebulizer treatments without wearing personal protective equipment (PPE).
“Because transmission-based precautions were not in use, no HCP wore personal protective equipment recommended for COVID-19 patient care during contact with the index patient,” the CDC concludes. “Healthcare facilities should emphasize early recognition and isolation of patients with possible COVID-19 and use of recommended PPE to minimize unprotected, high-risk HCP exposures and protect the healthcare workforce.”
In what is considered an underestimate, the CDC recently reported that more than 9,000 HCWs in the United States have been infected with novel coronavirus and 27 have died.
Despite the severity of a spectrum of cases, 90% of the HCWs recovered without hospitalization. In addition to overcoming fear to treat patients, the healthcare work force is proving resilient in the face of the COVID-19 pandemic.
“We always knew that healthcare workers would be essential to combatting pandemics, but I think you can see with this one, it is more true than many of us had anticipated,” Robert Redfield, MD, director of the CDC, said at recent meeting. “This virus is clearly one of the most infectious respiratory viruses that we have ever had to deal with.”
In CDC surveillance data from Feb. 12 to April 9, 2020, 9,282 (19%) of 49,370 COVID-19 case reports with occupational information were HCP.1 The information was gathered from CDC surveillance forms, and the numbers and percentages vary depending on the detail provided in individual reports.
“This [report] is likely an underestimation because HCP status was available for only 16% of reported cases nationwide,” the CDC stated. “HCP with mild or asymptomatic infections might also have been less likely to be tested, thus less likely to be reported. The total number of COVID-19 cases among HCP is expected to rise as more U.S. communities experience widespread transmission.”
Although only 6% of the infected workers were at least 65 years of age, 10 (37%) of the deaths occurred in this older age group. In addition, 38% of those infected had underlying risk factors, including asthma, chronic obstructive pulmonary disease, diabetes, cardiovascular disease, and immune compromised condition.
“Older HCP or those with underlying health conditions should consider consulting with their healthcare provider and employee health program to better understand and manage their risks regarding COVID-19,” the CDC recommended. “The increased prevalence of severe outcomes in older HCP should be considered when mobilizing retired HCP to increase surge capacity, especially in the face of limited PPE availability.”
One approach is to assign these workers to lower-risk duties, such as administrative tasks, the CDC noted.
Almost Half in Community Exposed
Breaking down the cases reveals that 55% of medical workers reported healthcare exposures, with the remainder citing household (27%), community (13%), or exposures in multiple settings (5%). The data reflect the “potential for exposure in multiple settings, especially as community transmission increases. Further, transmission might come from unrecognized sources, including presymptomatic or asymptomatic persons,” the CDC reported.
As the boundaries blur, it will be more challenging to make the distinction between community and occupational transmission to healthcare staff. More benign strains of coronavirus cause colds of unknown origin, but the severity of this infection raises issues of occupational health and workers’ compensation.
Among those who reported contact with a confirmed COVID-19 patient in a healthcare setting, details of the exposure and whether the worker was wearing PPE could not be determined. Among HCP patients with data available, the median age was 42 years. Among HCP patients with data available on age and health outcomes, 6,760 (90%) were not hospitalized. However, 723 (8% to 10%) were hospitalized, and 184 (2% to 5%) were admitted to an intensive care unit.
Although 92% of the HCWs reported having at least one symptom among fever, cough, or shortness of breath, the remaining 8% did not report any of these symptoms. Preventing asymptomatic transmission was one of the justifications for the recent CDC recommendation for all HCWs to wear surgical masks while on duty. Given the shift to community spread, contact tracing after occupational exposures is likely to be fruitless.
“Additional measures that will likely reduce the risk for infected HCP transmitting the virus to colleagues and patients include screening all HCP for fever and respiratory symptoms at the beginning of their shifts, prioritizing HCP for testing, and ensuring options to discourage working while ill, such as flexible and nonpunitive medical leave policies,” the CDC concluded.
- Heinzerling A, Stuckey MJ, Scheuer T, et al. Transmission of COVID-19 to health care personnel during exposures to a hospitalized patient – Solano County, California, February 2020. MMWR Morb Mortal Wkly Rep 2020;69:472-476.
- CDC COVID-19 Response Team. Characteristics of health care personnel with COVID-19 – United States, February 12-April 9, 2020. MMWR Morb Mortal Wkly Rep 2020;69:477-481.