A respiratory syncytial virus outbreak in a haematology ward at the Prince of Wales Hospital in Sydney has highlighted that severe infection can threaten patients not usually considered at high risk.
Dr Tomas Jensen and colleagues, writing in the Journal of Medical Virology, said most previously-reported outbreaks had been in patients having allogeneic haematopoietic stem cell transplants (HSCT), which are not performed at the Prince of Wales unit.
They suggested outbreak contingency plans be developed to also encompass populations not classically considered at high risk of severe RSV disease.
“We recommend increased vigilance for RSV on haematology wards, especially during the predictable community outbreak season,” they said.
“A threshold prevalence should be established, for example one or two diagnosed patients on the ward, which will trigger universal regular screening with PCR for RSV on nasopharyngeal swabs from patients and staff.”
Two of the 12 cases in the Sydney patients had had an autologous HSCT, and the remainder had been treated only with less immunosuppressive chemotherapies.
The first two cases died: a 42 year old man with multiple myeloma treated recently with an autologous HSCT and melphalan, and a 38 year old man treated with chemotherapy alone for non-Hodgkins lymphoma.
A thirteenth case occurred in a pregnant staff member.
Five cases had a lower respiratory tract infection and seven an URTI, and one case was asymptomatic.
Three patients with LRTI, and none with URTI, had a total lymphocyte count of 0.1 x 109 cells/L or less.
Patients with URTIs were treated with oral ribavirin for six days, and those with a LRTI received IV ribavirin. Three were not treated: one because of severe anaemia, one who refused, and the pregnant woman.
Sequencing of eight cases showed that five were caused by identical strains of the virus and three were strains commonly circulating in the community.
“Infection control measures should target both propagated spread within the ward and repeated introduction of new strains from the outside,” Dr Tomas and colleagues said.
The hospital’s multidisciplinary response included reinforcement of usual restrictions for staff and visitors on access to the ward, weekly screening of all patients and staff, contact and droplet precautions for patients with both suspected and confirmed RSV, and enhanced ward cleaning.
No more infections were identified later than two weeks after the plan was implemented.