Bollettino epidemiologico nazionale

School Exclusion Policies as a Measure for Infectious Disease Control: Review of the Evidence

Marta Luisa Ciofi degli Atti

Infectious Disease Unit

Laboratory of Epidemiology and Biostatistics

Istituto Superiore di Sanità, Rome

School exclusion for children with infectious diseases is a preventive measure that is designed to decrease secondary cases among other children. In the school setting, children and adolescents spend many hours in close physical contact, which increases the likelihood of transmission of infectious agents.

Internationally, a number of guidelines have been published on the recommended period of school exclusion for patients with infectious diseases (1,2). In Italy, the recommendations for school exclusion are contained in a circular of the Ministry of Health concerning the isolation of patients with infectious diseases (Measures of Prophylaxis for Public Health Purposes, Number 4, 13 March 1998).

The period of exclusion varies from disease to disease and depends primarily on the duration of infectiousness. However, many infectious diseases are transmissible from person-to-person even before the appearance of clinical symptoms, and the efficacy of exclusion is therefore a frequent topic of debate. Beyond the implications of the illness itself, school exclusion may cause problems for both the child and his family, especially in a society where there is an increasing frequency of single-parent families and households where both parents work.

A recently published article has presented the available data on the incubation period, duration of infectiousness, and the efficacy of school exclusion for 41 infectious diseases, selected because they were common or potentially serious in children of school age (3). For each infection, a systematic review of the literature published between 1966 and 1998 was performed.  The information available for each disease was categorized according to four progressive levels of evidence, and the three levels of policy recommendations (from A to C, in descending order) were made based on the strength of supporting data (Table 1).

More than 3000 articles were reviewed, of which approximately 20% provided useful information. Of the 41 infections under consideration, Class A recommendations were possible for only three diseases: chickenpox, Lyme disease, and tuberculosis. Seventeen diseases fell into Class B, and the remaining 21 in Class C. In general, the results of this study found a good correlation between the evidence supplied by the literature review and what is commonly reported in the infectious disease textbooks.

In this report, we have identified a series of 11 conditions from the 41 included in the study that are especially common or relevant in Italy. For these diseases, we have compared the recommendations from the above-mentioned article with Italian and U.S. recommendations. The results of this comparison are reported in Table 2.

As can be seen, the three sets of recommendations are similar, although the evidence-based recommendations raise several points that deserve further mention. In particular, the authors concluded that 5 days of exclusion is adequate for rubella and mumps, while for hepatitis A, the exclusion of children over 5 years of age is not recommended given that the infectiousness is greatest before the appearance of symptoms and that many children with the illness are asymptomatic. Exclusion is recommended for younger children, who often represent a source of infection for susceptible adults. Exclusion is not recommended either for infectious mononucleosis or Steptococcal pharyngitis. By contrast, the period of exclusion for scarlet fever based on the evidence review is greater than that recommended in Italy. Finally, in the evidence based review, data supporting policy for very common infectious such as head lice and Salmonella, the data were scarce, and recommendations for these diseases fell into Class C.

The systematic review of the literature is a very important instrument to evaluate the scientific evidence concerning the efficacy of preventive and therapeutic measures and in recent years has lead to improvements in many clinical fields. School exclusion is often recommended more out of habit than proven efficacy, and a review of the evidence is essential, not only to update recommendations currently in use and to identify areas where further data are needed.

References:

1. Anonymous. Guidance for infection control in schools. CDR Weekly 1999; 9: 269

2. Hale CM, Polder JA. The ABCs of safe and healthy child care: a handbook for child care providers. Atlanta, GA: Centers for Disease Control and Prevention, 1996

3. Richardson M, Elliman D, Maguire H, Simpson J, Nicoll A. Evidence base of incubation periods, periods of infectiousness and exclusion policies for the control of communicable diseases in schools and preschools. Pedatr Infect Dis J 2001; 20: 380-91