Our team has been doing a full review of outpatient / inpatient / transfer stats from our department's perspective for Jan-Mar 2012, which was a time period where we saw an epidemic of human metapneumovirus (hMPV) that overlapped an unusually severe season of RSV. We have issued several reports of our experience here in this blog. In Part 2, we explore further the "so what" of operational infectious disease forecasting coupled to early warning.
On the 25th of every month the Ascel Bio Black Canyon Infectious Disease Forecasting Station released forecasts for infectious disease activity specific to our county. RSV and other respiratory pathogens were therefore expected to appear and cause a given level of strain to our medical infrastructure.
From Jan 4th to Feb 10th, we admitted a low number of patients exhibiting typical RSV infection, where we followed American Academy of Pediatrics (AAP) guidelines for the management of RSV: no antibiotics, steriods, with the rare use of inhalers. In the midst of these admissions, the Station issued an advisory for unusual human metapneumovirus activity which at the time was primarily disruptive to the outpatient component of our medical infrastructure.
Then, from Feb 12-16th, multiple back to back admissions presented as typical RSV infections but abruptly decompensated on the floor, precipitating transfers for all of them to the Front Range by fixed wing aircraft. In the midst of this, we were told the Front Range's PICU grid capacity was close to diversion status. It was during this time we had report from the PICU that received our patients they were coinfected with Haemophilus influenzae. One of these patients would later be triply infected with Streptococcus pneumoniae while intubated.
On Feb 18th, a warning was issued by the Station, indicating an unusual epidemiological situation now existed for epidemic RSV of high clinical severity. Our department issued guidance to abandon standard AAP protocol for the treatment of RSV and consider the use of antibiotics prophylactically given the apparent high coinfection rate being seen.
Before the warning was issued to all providers with pediatric admitting privledges, our hospital exhibited a 33% transfer rate, all of whom were over the course of four days. Of those transferred, none of the patients were given antibiotics prophylactically upon admission. Forty-six percent of all admissions pre-warning were provided antibiotics for comorbid conditions such as otitis media.
After the warning was issued, the transfer rate dropped to 8%, as now 88% of RSV admissions were provided antibiotics prophylactically. Of total admissions to the hospital during the entire epidemic of RSV, 71% of the admissions were seen during the post-warning period. The 8% who were transferred were placed on antibiotics prophylatically, however it is not clear they were truly infected with RSV.
Adherence to the Station's warning heeded at least a 76% reduction in transfer rates due to RSV during the epidemic.
This is one of the rare examples of operational validity and proof of performance using near real time surveillance coupled to operational forecasting that altered the outcome of an epidemic.