When a bat is found in a household, the response can be quite variable. Many public health units may consider it a potential rabies exposure if the bat was in the house overnight, on the assumption that a bite could have occurred without being noticed (I have personal experience with that). Based on the large number of people that are given rabies post-exposure prophylaxis (PEP) for this type of exposure (and the large cost associated with PEP), along with an estimate that changing this policy would only result in an extra rabies case every few hundred years, many jurisdictions don’t automatically consider sleeping in a room with a bat to be exposure.
But, what about a situation where you have people who can’t reliably report whether they were bitten, who are immunocompromised, and for whom there is no information about whether rabies PEP is safe or effective?
That situation occurred in a neonatal intensive care unit (NICU) in Austin, Texas, as reported in Infection Control and Hospital Epidemiology (Bailey et al 2016).
Two bats were found in a sink in the NICU… a strange place for them to be, and any time bats are in a strange place or acting abnormally, it’s a big red flag that they could be rabid. The bats were released outside, so they could not be tested. That means you have to err on the side of caution and assume they were rabid, then determine whether there might have been any human exposure.
While there was no evidence of them having contact with any patient, there’s no way to rule that out since bat bites can be very small and hard to detect, and the patients in a NICU obviously can’t report a bite.
After considering various factors, such as the nearly 100% fatal nature of rabies infection, the lack of evidence of vaccine effectiveness or safety in premature infants, and the known potential for poor response to rabies vaccination in people with compromised immune systems, it was decided that at least some of the infants should receive PEP (the paper doesn’t describe how those were selected). Rabies vaccination was recommended for 6 and offered for the 13 other infants in the NICU. Families of 5/6 of the high risk and 2/13 of the lower risk group consented to the PEP. None of the patients developed rabies.
The paper provides some information about response to rabies vaccination. None of the infants developed any identifiable complications. Three infants were tested 6 moths after treatment, and all had developed an adequate immune response (circulating rabies antibodies). It’s a small number of patients, but provides at least some indication that premature infants can mount an effective response to rabies vaccination.
There’s no mention of what they did to figure out how the bats got into the NICU or hanging around in the hospital, nor if they provided any subsequent training to make sure people don’t just release bats that are found inside.