An article published in the August edition of The Lancet Infectious Diseases studies how the closing of schools during flu pandemics causes a health, social, and economic impact. The review is the work of Dr Simon Cauchemez and Professor Neil Ferguson, Department of Infectious Disease Epidemiology, Imperial College London, UK, and collaborators. They examined data from earlier epidemics and pandemics worldwide. They conclude that extended school closure early on can considerably relieve saturated hospitals by reducing the number of cases at the highest point of the pandemic. On the other hand, it is uncertain if the intervention would have a major impact on the total number of cases. Also, it is linked with high social and economical costs, and could potentially disrupt health care systems and other vital services. In closing, the review indicates that the ultimate decision to close schools for extended periods should cautiously consider the severity of the pandemic.
In the current H1N1 flu pandemic, children appear to be central vectors of transmission. More than 60 percent of cases are aged 18 or younger and children are more infectious and susceptible to most flu strains than are adults. These factors may be strong arguments for school closure in the current H1N1 flu pandemic. The authors write: “It is therefore hoped that closure of schools during the pandemic might break the chains of transmission, with the following potential benefits: reducing the total number of cases; slowing the epidemic to give more time for vaccine production; and reducing the incidence of cases at the peak of the epidemic, limiting both the stress on health-care systems and peak absenteeism in the general population, and thus increasing community-wide resilience.”
Still, there can be a negative effect of school closures on workers that have a critical function, such as doctors and nurses who are also parents. As a result, they may have to miss work to look after children during an extended school closure. But since schools could need to close anyway due to teachers being sick, the authors suggest ‘it would seem sensible for all countries to at least have plans for reactive closure’.
The article analyzes different preceding flu outbreaks. In 2000, a teacher strike in Israel during a flu outbreak was associated to reductions in doctor and emergency department visits. There were also reports of reductions in weekly numbers of respiratory tract infection diagnoses and of viral infections. The strike ended while the outbreak was still in progress and when schools reopened, the infections increased again. A study of school holidays in France from 1984 to 2006 indicates that school holidays prevent one in six seasonal influenza cases. This means that there would be 16 to18 percent more people infected each year if schools had no holidays and were open all year. This French study suggests proactively that the closing of schools could decrease flu cases by 13 to 17 percent in general. During the peak of the outbreak, the decrease could be of larger proportions of 38 to 45 percent. Finally, studies of the 1918 pandemic in US and Australian cities suggest that school closure in combination with other measures including church closures, better hygiene could have reduced mortality by 10 to 30 percent. The reductions would have been larger in peak mortality (as high as 50 percent in some cities). On the other hand, the strategy did not appear to have any considerable impact on spread when it was implemented during the 1957 pandemic in France or during a seasonal outbreak in Hong Kong.
Infection control is only one part of the subject matter of school closures. UK and US studies have estimated the cost of a twelve week closure between 1 and 6 percent of GDP (gross domestic product). School closures would also have an extreme effect in poorer socioeconomic groups. For example, it would cause the disruption of social programs such as free meals that take place at schools.
The effects on the health-care system could also be serious and long-lasting. In the UK, 30 percent of the health and social care workforce is likely to be the main caregiver for dependent children in comparison with an average of 16 percent across all sectors. As a result there could be substantial levels of absenteeism from work from the health workforce during a pandemic to look after children, in addition to absences caused by illness in healthcare workers. A survey of the UK Department of Health found that 77 percent of respondents were women. In the UK, 78 percent of doctors and nurses are female. Of these, 50 percent had a dependent child aged less than 16 years and 21 percent said they would most likely not attend work if schools closed. Sadique and colleagues have estimated peak absence from the healthcare workforce during a pandemic at 45 percent. With 30 percent due to school closure, 10 percent due to sickness, 5 percent due to other causes.
The closing of schools creates many operational issues which can be solved but that require cautious local planning. School closures will not be achievable in all countries and settings, even if they might be necessary from a strictly health care standpoint. Existing models suggest that if schools close before 1 percent of the population becomes sick, the effect of closure remains close to maximum. Clearly countries could execute this on a regional basis, but the timely activation for closure would be essential. Waiting for elevated levels of school absenteeism could imply the closure was overdue. Many complicated issues would need to be addressed, such as how long should schools remain closed and whether children could receive schooling at home. But all schools should plan for these decisions as absenteeism of their own staff could be the trigger for closure. The authors comment that there is a need for studies on outbreaks at schools including the phase before, during, and after closure, along with the social and economic impact of the closure on households. The effect of closure on transmission in the larger community must also be evaluated.
The authors remark that the resolution to close should also be based on the severity of the pandemic. They write in conclusion: “The H1N1 pandemic could become more severe, and so the current cautious approach of not necessarily recommending school closure in Europe and North America might need reappraisal in the autumn. Another important uncertainty for pandemic planning is that individuals are likely to change their behaviours during a pandemic in a way that is difficult to predict. There is, for example, evidence that people reduced their contacts during the pandemic when mortality was high. The ways children mix with each other during a prolonged school closure remain a key uncertainty, likely to be influenced by the severity of the pandemic.”
“Closure of schools during an influenza pandemic”
Simon Cauchemez, Neil M Ferguson, Claude Wachtel, Anders Tegnell, Guillaume Saour, Ben Duncan, Angus Nicoll
Lancet Infect Dis 2009; 9: 473-81
“Estimating the costs of school closure for mitigating an influenza pandemic”
Sadique MZ, Adams EJ, Edmunds WJ
BMC Public Health 2008; 8: 135
Written by Stephanie Brunner (B.A.)