Fatal outbreak of chickenpox (varicella-zoster virus infection) among institutionalised adults with learning...

Most adults are not susceptible to chickenpox. We present a report of an outbreak of chickenpox among institutionalised adults with learning difficulties. An inventory of exposed and possible affected residents was done after three adult males were diagnosed with chickenpox following a case of zoster. Individuals with a recent history of chickenpox rash or herpes zoster were included as cases. Medical files were used to derive background information. Serum samples of the first two patients were tested for IgM varicella-zoster virus (VZV) antibodies. Eventually ten cases of chickenpox (eight residents and one group leader and her partner) and two residents with herpes zoster were registered over a period of four months in 2001. The first two patients tested positive in serum. One resident with chickenpox died. This outbreak suggests a higher risk from chickenpox for institutionalised adults with learning difficulties in comparison with the general Dutch population, probably due to limited contacts with the general population. Further research into varicella-zoster seroprevalence, preferably with low-invasive diagnostic methods, is necessary to determine if this potential risk is present elsewhere, since the risk of life-threatening chickenpox in adults could be reduced by the now available live attenuated VZV vaccine.