Varicella vaccination is not recommended for listed contraindications that include pregnancy. An important risk for HCWs is the inadvertent vaccination of pregnant individuals. In the United States, surveillance of inadvertent immunisation of pregnant women with the Oka/Merck strain (VARIVAX) has not identified any specific risk to the foetus (2). The establishment of such a register, to monitor possible sequelae following such an event, is a feature of the recent recommendations in the (UK).

The UK is one of the first European countries to publish official recommendations for varicella vaccination. A survey of the immunisation policies amongst countries participating in the European Sero-Epidemiological Network (ESEN2, http://www.hpa.org.uk/hpa/inter/esen2_menu.htm) has recently been undertaken. A wide variety of different policies for varicella vaccination have been implemented or are being considered amongst the participating countries. The immunisation of seronegative professional HCWs has (or is) being considered by only a handful of other European countries. Interestingly, in some countries, a recommendation to vaccinate all seronegative individuals involved in the care of children is also being considered.

Vaccination against varicella has been recommended in the United States for all susceptible people aged 12 months or older since 1995 (3). Of those countries participating in ESEN2, only one country has introduced (in 2001) mass vaccination against VZV targeted at a similar age group as the US vaccination. However, concerns have been raised of the effectiveness of such a strategy, as it may result in an increase in cases of zoster disease, because of the lack of boosting of immune responses in older individuals (4,5). Furthermore, a mass vaccination campaign with a suboptimum coverage could result in an increase in the average age of infection to those ages in which the disease and its sequelae are more severe (4).