In-Hospital SARS-CoV-2 Transmission Low in Cancer Patients

By Reuters Staff

August 17, 2021

NEW YORK (Reuters Health) - The overall risk of hospital-acquired COVID-19 is low for hospitalized cancer patients, but sharing a room may boost the risk, researchers say.

Beyond an outbreak setting, little information is available on the risk of hospital-acquired COVID-19 in high-risk patients, Dr. Mini Kamboj and colleagues from Memorial Sloan Kettering Cancer Center, in New York City, explain in Clinical Infectious Diseases.

They recommend biweekly asymptomatic healthcare worker (HCW) testing in inpatient and procedural settings and note that in 2020 their institution started universal SARS-CoV-2 testing of patients at admission.

However, they also point out that early in the infection, the virus may not be detectable and analytic limitations or poor sampling may lead to false-negative results. As a result, patients were retested every three days during their hospital stay.

Between March 2020 and February 2021, a total of 11,348 patients were found to be SARS-CoV-2 PCR negative at their initial test at the time of admission. They then went on to receive a further 31,662 tests during their hospitalization regardless of COVID-19 symptoms.

In all, 112 patients (0.98%) tested positive. Of these, 49 had been housed in semi-private rooms which account for 57% of the beds in the institution. Fourteen of the patients were identified on a symptom-triggered COVID-19 test and 35 tested positive on a surveillance test.

These patients had been housed for a median of three days in a shared room resulting in 74 close-contact exposures in their roommates and 14 secondary infections within 14 days. This corresponded to an overall attack rate of 18.9%, while among those exposed to a roommate undergoing an aerosol-generating procedure, the attack rate was 35.7%.

Whole-genome sequencing corroborated transmission in six of eight evaluated pairs.

During the study period, more than 17,000 employees were tested and 105 COVID-19 positive workers in the inpatient setting were identified. Three transmission events occurred in 214 patients with significant exposure to these workers (1.4%). Whole-genome sequencing confirmed transmission in the two pairs with adequate viral load.

The researchers note that their study predates broad dissemination of vaccines, so their impact in patients and healthcare workers was not measure. But there is an overall low risk of hospital-acquired COVID-19 among immunocompromised patients even with high SARS-CoV-2 community prevalence.

They advise that "post-exposure prophylaxis should be considered for patients in shared occupancy after exposure to an infected hospital roommate."

Dr. Kamboj was unavailable for comments.

SOURCE: Clinical Infectious Diseases, online July 30, 2021.