Introduction
An influenza pandemic is of enormous significance both nationally and globally because it affects a large number of people. Historically, four principal influenza pandemics (1918, 1957, 1968-9, and 2003) have been reported globally. In 2003, the pandemic involved outbreaks of Influenza A, subtypes H1N1 and H5N1, and an outbreak of acute respiratory syndrome.
The suggested influenza mitigation strategies can be classified into two main categories; pharmaceutical (vaccines and antiviral) interventions, and non-pharmaceutical (travel restrictions, school closure, household quarantine, and isolation of infected individuals) interventions. Before the implementation of an intervention, its potential benefits must be weighed against its social and economic costs. Mathematical models are vital tools for investigating the potential benefits against the costs of a particular pandemic intervention strategy.
School closure was the strategy considered by the Centres for Disease Control (CDC) to mitigate virus transmission during the 2009 influenza A H1N1 pandemic. The rationales for this strategy were that children are more susceptible to influenza viral strains compared to adults and that high interaction frequency in school favors transmission. Studies indicate that school closures significantly reduce the transmission rates of influenza, which contribute to reduced morbidity and mortality rates. Although the measure has significant health benefits, it nevertheless generates a substantial debate as to how, if, and when the policy should be used in schools.
This paper describes the school closure intervention in the Australian context in response to the outbreak of influenza (H1N1) pandemic in 2009. It outlines the intervention and its aims as well as the current Australian guidelines that inform intervention measures for the influenza pandemic. The paper will also explore the effectiveness of the school closure measure, its benefits versus the disadvantages as well as the challenges of its implementation. Finally, recommendations on the intervention supported by evidence from previous studies will be given.
Brief Description of the Control Measure
School closures in Australia occurred in 2009 when the transmission rate of influenza A (H1N1) was high across the country. The purpose of this measure was to reduce the spread of the disease and involved temporary closure of schools at different levels; local district level in the beginning to countrywide closures afterwards. School closure is a recommended intervention during an influenza pandemic to break the chains of transmission among the population.
The health effects of the school closure were quite substantial. It resulteinto a reduction in the number of infected cases as student-to-student contacts declined. However, the intervention also produced opposite results; it enhanced student-community contacts and thus accelerated the spread of the H1N1 pandemic. In addition, the proactive school closures resulted in social issues such as personal inconveniences, loss of wages, and issues of childcare. This implies that the implementation of the school closure policy needs careful consideration with regard to its social and economic costs on the general population. In light of this, the CDC provides revised guidelines that largely advise against proactive school closures but recommend planned reactive closures for severe cases of H1N1pdm infection. Thus, the decision to implement the school closures policy should take into account the potential economic and social costs associated with school closure as well as the ethical issues raised by such a policy.
Current Australian guidelines regarding this measure
The plan for a school closure policy should focus more on the social, economic, and ethical issues associated with the policy. The Australian Health Management Plan for Pandemic Influenza recommends a holistic and multidisciplinary approach to school closure following an H1N1 outbreak. Accordingly, the school closure policy should be implemented at an appropriate time, when the epidemiological trends of the H1N1 strain have been fully understood. Additionally, the guidelines recommend a coordinated communication of the policy by the states or territory governments to administrators and employers, especially regarding reactive closures.
Evidence from previous influenza pandemics provides the rationales for school closure policy. Firstly, children are more susceptible to many influenza viral strains than adults are and consequently have higher infection rates. Secondly, children take longer to develop the symptoms of the infection than adults. This means that children compared to adults can be vectors of transmission and are more infectious. Thirdly, children are less likely to adopt preventative measures such as hygiene to curb the spread of the H1N1 infection. These reasons provide strong arguments for school closures in pandemic outbreak situations. The school closure policy, therefore, should reduce the H1N1 infection rates by primarily reducing infection among children and by extension the rates of transmissions in the community.
In Australia, the response to influenza pandemics involves five distinct phases; alert phase (informing the public of the outbreak), delay phase (public response to the pandemic), contain and sustain phase, prevention phase and recovery phase. Of most significance, however, is the delay phase, where the level of public response to the pandemic produces a corresponding impact on the transmission rate of infection in the community. The delay phase encompasses the various measures the public undertake to enhance their protection and increase communitywide resilience in pandemic outbreak situations.
Critical review around the level of effectiveness
Evidence from previous studies indicates that, children have high infection rates and more vulnerable to pandemic infections than adults. Consequently, non-pharmaceutical interventions such as school closures target the children both as the vulnerable group and as distinguished vectors of transmission. School closures can take three different forms: a class closure in case of an isolated case of infection, single-school closure after many cases have been reported in a single school and reactive closure of many schools after many diagnosed cases of the pandemic in a region or country.
Epidemiological effects
The impact of non-pharmaceutical interventions such as school closure on the spread of a pandemic can be determined through mathematical modelling. The results of some models imply that school closures alone may not necessarily achieve the expected outcome i.e. reduce the transmission of the pandemic, especially if the children are not adequately isolated at home settings. By contrast, other models suggest that a combination of school closures and sufficient isolation children or keeping children apart in home settings can effectively reduce the peak incidence rates but will achieve only marginal effects with regard to reduction of pandemic scale.
The variations in the assumptions made in the different models give rise to different modelling outputs. For instance, if an assumption that 50% of pandemic transmission takes place in schools, then school closures will be expected to achieve higher outcomes i.e. reduction in transmission rates. In contrast, if the assumption is that 20% of transmissions occur in school settings, then the outcome expected from school closure intervention will be much lower. Nevertheless, either the 20% or 50% transmission rate assumption may not entirely determine the outcome of an intervention.
Additionally, the impact of school closures on transmission rates depends on the level of intervention; short-term or long-term school closure. Aledort et al modelling simulation considered the impacts of school closures on the transmission rates. From their simulation results, they established that school closure causes a delay in peak day (PD) and simultaneously reduces the attack rates (AR) of the pandemic. This implies that, short-term interventions, such as single-school closure, can achieve positive outcomes at considerably lower economic and social costs. However, if the prime target is to reduce the epidemic size, then longer school closure is pivotal in achieving a delayed PD and a lower AR.
In contrast, computer models indicate that temporary school closures significantly reduce the rate of influenza transmission in the population. However, these models make two assumptions; family and student behaviour during school closures do not contribute to the spread of the disease. In particular, these models assume that children remain at home with their parents during school closures to minimize indirect workplace transmissions. Additionally, the models assume that parents’ behaviour will result to low-level interactions among children in the community.
Aledort et al notes that the computer models simulate of reality but fail to include the dynamics of human interactions in the community. This means that models, though they provide valuable information on possible case scenarios and trends transmissions that inform health policy decisions, they cannot, by themselves, adequately define the intervention. For instance, an influenza outbreak and epidemiological patterns may fail to conform to the assumptions or data of any model because of the multiple social aspects associated with non-pharmacological interventions such as school closures.
Behavioural effects
Various behavioural factors influence the outcomes of the school closure intervention. The geographical location i.e. whether rural or urban, individual perceptions regarding the strategy as well as the associated economic costs of the intervention influence the level of compliance and by extension the effectiveness of the strategy. For instance, Cauchemez et al found that, households allowed children contact when school closures were implemented in rural and suburban settings, in 2006 and 2009, in Pennsylvania and North Carolina respectively. In contrast, in New York City, 40% fewer households reported allowing their children outside their residential homes during school closures.
Another behavioural factor, which influences compliance to school closure policy, involves challenges with childcare. A study conducted in Pennsylvania established that most parents reported personal inconveniences because of school closures. However, the same households reported no loss of time from work normally associated with increased childcare responsibilities. In this survey, more than 50% of the household had a nonworking adult person at home. This explains why fewer adults reported lost time from work in the locales surveyed. Additionally, more adults working away from their residential homes reported lost time from work compared to those working from homes. This implies that the school closures led to personal inconveniences with regard to childcare especially to parents working far from their residential homes.
Additionally, people’s perceptions regarding the policy may affect compliance patterns. Milne et al study demonstrated that only 47% of parents believed that school closures could contribute to reduced transmission child-to-child transmission. The parents suggested that the school closures were inappropriate citing the mild nature of the epidemiological characteristics of the pandemic as the main reason. Thus, effective communication of the health policy to parents especially regarding the benefits and potential social and economic costs can help foster parental involvement and enhance the effectiveness of the strategy.
Advantages and disadvantages of the school closure
Although the school closure policy has some health benefits, it also has social and economic costs. The economic costs arise from lost wages caused by the absenteeism of working parents who have to assume childcare responsibilities following school closures. For instance, school closures 2009 H1N1 epidemic forced parents to miss work and provide childcare for their children. School closures also raise many issues regarding social justice and ethics. In particular, self-care, where a child is left in his or her care or under the care of a minor, presents serious social risks such as drug use and underage drinking.
Other interventions such as vaccination, in comparison, have a lower cost per case averted. This means that alternative interventions are much cheaper, and more effective compared to the school closure strategy. Thus, school closures may not have been a viable mitigation strategy for the 2009 H1N1 pandemic. Halloran et al found that pre-vaccination and targeted antiviral prophylaxis (TAP) measures are more cost-effective and can reduce transmission by 48% and 54% respectively.
The chief health benefit of school closures is the reduction in incidence rates during peak situations. In this way, the chains of transmission are broken and consequently slow down the spread of the pandemic. The potential benefits of school closure include a reduction in the infected cases, reduction in incidence rates, which allows more time for vaccine production, and reduction in incidence rates during peak times, which eases stress on health facilities and workplaces.
Recommendations for the current policies and guidelines of the measure
Effective pandemic intervention should involve a multidisciplinary approach that considers the social, ethical, and economic aspects of the public health policy. This means that school closures should not occur in isolation, but instead, they should be used in conjunction with other mitigation strategies. In the 2009 H1N1 epidemic, school closures were the viable primary mitigation strategy as a vaccine was not available initially. However, a multidisciplinary approach or targeted-layered containment that combines different intervention strategies (known as) and has been shown to reduce influenza transmission effectively. In addition, besides the school closure mitigation strategy, other strategies that target other population cohorts can contribute to an effective reduction in infection rates.
Moreover, the school closure policies need to include additional measures that limit children contact in home settings. Evidence from previous studies indicates that contact among students in out-of-school settings enhances the spread of the infection. This implies that school closures should involve strategies to minimize contact in other settings where students congregate setting other than the school. Contact in other settings can also increase the spread of the pandemic and consequently reduce the benefits of school closure. In addition, the school closure decisions should take into account the social justice and ethical issues. For example, in school-based programs, the implementation of the school closure policy can adversely affect the well-being of the children in terms of nutrition.
Self-care that arises from school closure has many associated risks. In particular, Morse et al identify adverse peer pressure as a leading behavioral problem associated with self-care. Drug abuse and substance use are other social vices associated with self-care. Thus, social justice and ethical issues should be considered when adopting the school closure policy.
Conclusion
School closure policy is a primary non-pharmaceutical intervention that aims at reducing the incidence rates of the H1N1 pandemic and slowing down its transmission. It targets the children because they are the vulnerable group and are crucial vectors of transmission. Mathematical modeling and evidence from past seasonal influenza infections inform the school closure strategies. The school closures during the 2009 H1N1 pandemic, though beneficial, had significant social and economic costs. Thus, a multidisciplinary approach that encompasses all interventions is essential in achieving positive outcomes.
Reference List
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Mikolajczyk RT, Akmatov MK, Rastin S, Kretzschmar M. Social Contacts of Schoolchildren and the Transmission of Respiratory-Spread Pathogens. Epidemiol Infect 2008; 136:813–22.
Cauchemez S, Ferguson NM, Wachtel C, Tegnell A, Saour G, Duncan B. Closure of Schools during an Influenza Pandemic. Lancet Infect Dis 2009; 9:473–81.
Halloran ME, Ferguson NM, Eubank S, Longini IM Jr, Cummings DA, Lewis B, et al. Modelling Targeted Layered Containment of an Influenza Pandemic In The United States. Proc Natl Acad Sci 2008; 105:4639–44.
Milne GJ, Kelso JK, Kelly HA, Huband ST, Mcvernon J. A Small Community Model for the Transmission of Infectious Diseases: Comparison of School Closure as an Intervention in Individual-Based Models of an Influenza Pandemic. Plos One 2008; 3:4005.
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