It began with a handful of Russian children being exposed to a stomach virus, and the last week of July has presented the best example yet of why vaccination works. At a water park in France, three children were found to have suffered severe gastrointestinal sickness after ingesting water from a tank that had not been cleaned. Then, when rescuers moved the pump room of the water park, they found more rashes.
In the immediate aftermath of the outbreak, authorities in France ordered the closure of four water parks across the country. Twenty-one children showed symptoms after coming into contact with the contaminated water. The children were offered vaccinations, and have all since recovered, but the virus may have spread. Another case was confirmed in June, and now there are more.
The hospitalization of children doesn’t diminish the importance of vaccinations, and in the West at least the evidence that they work appears to be growing stronger by the day. Numerous clinical trials have proved the efficacy of vaccinating against the measles, which remains a public health threat as close as our own cities. Measles vaccine is available for free, and vulnerable populations are routinely vaccinated through the World Health Organization.
But this month’s outbreak is the latest case of our failure to scale-up the measles vaccine.
As often occurs with vaccine emergencies, the announcement of more cases had nearly identical language. Public health officials said that the respiratory illness was “confirming the risk” of the disease spreading.
We’re turning out to be terrible readers of warnings.
There were plenty of scientific studies in the 1990s and 2000s looking at the likelihood of acquiring the measles, which warned that the vaccine did not completely prevent illness. It did not, and with each outbreak its widespread use has reduced the severity of the disease. For example, between 1995 and 2004, incidence of measles in France fell to zero, and American measles incidence dropped to just 37 cases between 2000 and 2013.
But these studies were made before vaccination was common. The shocking death of one child in September at a water park highlights our failure to account for all the factors that may come into play when a vaccine is administered.
It is hard to explain a child’s death with standard measures that focus on causal factors (e.g., a pregnant woman died suddenly. No one knew).
But one more time, it was swimming pools that were closed and pool cleaners and sanitation systems disinfected before the children’s families came down with a rash.
Any parent will tell you that we have gotten remarkably serious about cleaning our pools since the introduction of chlorine. Swimming pools were littered with water and sand as early as the 1960s, and many swimmers frequently submerged in “kill traps,” where chlorine seeped from the sand beneath their feet. There were few clean bathrooms and bathing areas. The various gee-whiz devices in the bathroom, such as O-tips and dilute tapes, made no actual cleaning possible.
Since the introduction of a 16-fold increase in chlorine concentration — a threshold that supposedly kills most bacteria — our pools are clean again.
We can’t reduce risk by doubling chlorine levels for every disinfectant we add. That is, we won’t eliminate the chance of infection when we set our goal unrealistically high.
We can increase infection-prevention where there has been an improvement, for example, and by broadening participation in vaccine campaigns. A few common-sense steps might go a long way.
For example, in one chlorine-efficient swimming pool in the United States, the lines are often fouled with liners that have been sucked into the chamber. These are common problems in pools, especially those in which the liner has “nested” near the gills of the pool. This damage is rare in pools with special pressure-relieving liners.
These aren’t the type of things that go unnoticed when people are out of sight, but they can be solved by a list of common-sense measures. Making some grubby liners a daily culprit in the average household can help filter the pool and make them less prevalent among larger swimmers.
It’s too late for the one child who died in this outbreak, but the evidence that these types of problems can be easily solved by common-sense disinfectant filtration solutions is another lesson from recent history that the old methods of managing infectious disease shouldn’t be abandoned.
Joanna Lash is the Managing Director of the Human Safety Institute, which focuses on human safety and health in workplaces and schools.