Lessons for Mumbai from the American measles outbreak

The United States believed that they eliminated measles, but the country has just reported one of the largest outbreaks of the disease.

Two counties along the Washington-Oregon border have reported 72 cases, mostly among unvaccinated children. The outbreak reportedly began when an infected visitor came into contact with children who had not been inoculated.

The question being asked in the United States is why there has been an outbreak in a relatively remote area. One reason is that Washington and Oregon are among 17 states that allow parents to refuse vaccination of their children. Washington has been described as a ‘hotbed’ of groups – called ‘anti-vaxxers’ – which campaign against mandatory vaccinations.

The World Health Organization (WHO) has said there has been a 30% rise in measles cases worldwide – including in places where it was thought to have been eliminated. WHO says global measles deaths have decreased from 5,50,100 in 2000 to 89,780 in 2016, but the disease is a public health issue, with an estimated 7 million people infected in 2016.

Measles is highly contagious – the virus can spread through droplets expelled by coughing and sneezing. The pathogen survives in the air or on infected surfaces for up to two hours, with the potential to infect up to 14 others. While symptoms can be mild, the infection can cause deadly complications like pneumonia.

Washington’s health department, in its public notification, has said the best protection against measles is the MMR (measles, mumps, rubella) vaccine, which is effective against all strains of the virus. WHO recommends, as the standard for all national immunisation programmes, reaching all children with two doses of measles vaccine, either alone, or in a measles-rubella (MR), MMR, or measles-mumps-rubella-varicella (MMRV) combination.

The introduction of the vaccine had almost eliminated the disease in advanced countries though not everyone has been vaccinated. The disease gets eliminated if a community achieves high levels of immunisation. This is called herd immunity but this protection is weakening because of a drop in vaccination rates. Europe and New Zealand have declared measles outbreak emergencies. The WHO has said that the anti-vaccination movement is among the top 10 public health threats.

Mumbai’s measles rubella vaccination programme, which began on November 27, is meeting similar resistance.

The vaccination is not mandatory in India, but it is essential if the disease is to be controlled. The public health department declares an outbreak of the disease if there are five or more cases in one area. There have been cases reported across the state but no outbreaks.

In Mumbai, the immunisation programme has covered 22,20,000 children so far, but the numbers are not adequate to achieve ‘herd immunity’.

Dr Chandrashekhar Chiplunkar, assistant health officer in charge of the immunisation programme, said that for a community to develop herd immunity the WHO recommends a 95% immunisation rate. He estimates that the percentage of children vaccinated in Mumbai is currently 89%.

“Most cases of children who have not been vaccinated are refusals,” says Chiplunkar.

Misinformation and fake news have been the main obstacles against the achievement of high vaccination rates.

In the West, a study that linked the MMR vaccine to autism derailed the universal vaccination programme. The study has been retracted as false but other rumours continue to obstruct the campaign. Chiplunkar said that social media posts, many of them sourced from neighbouring countries like Pakistan, call the vaccination drive as a surreptitious project to sterilise children.

“This is the main reason for the refusals. Elite schools and minority communities have their own issues and taboos. We have asked maulvis (religious leaders) to get involved in the campaign (to dispel the rumours) but there have been no proper results.”

Vaccine refusal is not a new development. There was vaccine refusal during smallpox eradication. There was vaccine refusal for polio. Smallpox has been eliminated and polio is restricted to Nigeria, Pakistan and Afghanistan.