First the quake, now the disease. The earthquake in Nepal on 25 April drove 2.8 million people into tents with little clean water or sanitation. Infections like hepatitis and diarrhoea are now appearing, but the biggest fear is cholera.
It hasn’t appeared yet, but it hits Nepal every rainy season. Those rains are due in June.
Yet, help is on the way. Nepal has an emergency vaccine to try to head off cholera, a first in such a natural disaster.
This is because of a vaccine stockpile set up in response to the cholera that struck Haiti after an earthquake in 2010 – cholera carried there, ironically, by Nepalese peacekeepers.
It will be no panacea; cholera experts stress that supplying clean water and toilets, and isolating and treating any cases, are still essential. But Nepal also now has 18,000 doses of Shanchol, an oral vaccine made of dead cholera bacteria by Shantha Biotechnics of Hyderabad, India.
Full immunity requires two doses of vaccine, two weeks apart, so that is only enough for 9000 people – and it will be difficult to ensure people in camps get both doses. In a final hurdle, the vaccine must be refrigerated.
The WHO, other agencies and the Nepalese government will now assess where people are least likely to get clean water in coming weeks and where it will be possible to vaccinate people successfully, says Dominique Legros of the World Health Organization. Then more vaccine can be flown in from the WHO stockpile.
“We must not wait for outbreaks to start,” says Legros; it takes another week after the two doses for immunity to develop. Legros helped organise the first emergency use of the vaccine last year, in four camps of people displaced by fighting in South Sudan. “It really worked well.”
Researchers had discussed a vaccine stockpile before the Haitian epidemic. But in a cholera outbreak, many catch and spread the bacteria without getting sick, making it hard to tell who will still benefit from vaccine.
The WHO first recommended using vaccine during epidemics in 2010, after Haiti exploded. But when exactly to use vaccine in a pre-emptive strike was not clear, says Louise Ivers of Partners in Health, a health non-profit in Boston.
And there was not much to use. The only oral vaccine approved by the WHO in 2010 was expensive and bulky. It approved Shanchol, which was cheaper and easier to use, in 2011, but there wasn’t much of either. Neither cause long-lasting immunity, so children in countries with cholera aren’t routinely vaccinated, meaning the market was small and not much was made.
In 2011, with the Haitian epidemic still raging, cholera researchers called for a vaccine stockpile partly to give manufacturers a bigger market. In 2012, to settle doubts about whether vaccination campaigns are possible during an epidemic, Ivers and colleagues vaccinated a rural community in Haiti. This year they reported that those people were subsequently 65 per cent less likely to get cholera.
In 2013, the WHO started the stockpile. “The Haiti epidemic was so huge it shook up the world of cholera experts,” says Ivers. “It was a big impetus to move forward with a vaccine stockpile.” “The epidemic in Haiti clearly had an impact,” says David Sack of Johns Hopkins University in Baltimore.
It now holds 2 million doses, and Gavi, the Geneva-based organisation that helps poor countries buy vaccines, plans to increase that to 20 million a year by 2018.
A cholera outbreak is a high probability in Nepal now, says Anuj Bhattachan of the International Vaccine Institute in Seoul, who is in Nepal. “The key mantra for us is not another Haiti situation,” with cholera spreading virtually unchecked, he says.
“If we mobilise cholera vaccination soon, along with sanitation, there will be immense immune protection.” The decision, he says, is now up to the Nepalese government.
Source: NewScientist – Health