'Ground breaking' typhoid vaccine reduces infections by 80 per cent in Nepal

Sarah Newey
A student in Pakistan receives the new anti-typhoid vaccine, which has performed impressively in the first field trial - REUTERS

A “ground breaking” typhoid vaccine has reduced cases of the bacterial disease by more than 80 per cent in a trial involving 20,000 children in Nepal.

It is the first time the inoculation, typhoid conjugate vaccine (TCV), has been tested in the field but experts say the “exciting” results could be a turning point in efforts to combat drug-resistant typhoid infections. 

The highly contagious disease, caused by Salmonella Typhi bacteria, spreads rapidly in areas with poor sanitation and dirty drinking water and is a leading cause of fever among children. Each year, nearly 12 million people are infected and between 128,000 and 160,000 die. 

But Salmonella Typhi is increasingly resistant to the antibiotics typically used to treat typhoid, so experts say that new vaccines are vital to prevent infections occurring in the first place. 

“There is a problem with antibiotic resistance almost everywhere with typhoid,” said Andrew Pollard, professor of pediatric infection and immunity at Oxford University.

“For instance in Pakistan, the strain that is circulating has become resistant to almost all antibiotics - certainly the conventional ones used for typhoid. 

“That means standard treatment doesn’t work, you spend more money on more expensive antibiotics, and children don’t get better. Having a vaccine that prevents an infection in the first place is really going to be ground breaking,” he said. 

TCV is not the first typhoid vaccine developed, but current innoculations do not work well in young children and provide protection only for a few years.

The World Health Organization has already recommended the use of TCV in children and infants in typhoid-endemic countries, after impressive results in “human challenge” trials in the UK.

These studies involve healthy volunteers receiving the vaccine and then being infected with typhoid - often cash-strapped students

But Prof Pollard told The Telegraph that the field trial was vital to demonstrate that the vaccine was safe and effective in endemic populations. 

The study, published in the New England Journal of Medicine, involved 20,000 children between 9 months and 16 years of age in Nepal. Half of the children were given TCV, and their cases of typhoid fell by 81 per cent in the first year of the trial. 

“The fact that there was such a dramatic reduction in children is very exciting,” said Prof Pollard. “Previous studies were in adults, so it was not known how effective TCV is in the population under 15.”

The vaccine is now being rolled out in Pakistan, which has seen an outbreak of extensively drug resistant (XDR) typhoid fever since 2016, with Sindh province at the heart of the outbreak.

Gavi, the Vaccine Alliance, has announced that it will fund vaccinations for nine million children, and Sindh province will become the first region in the world to include TCV in routine childhood immunisations. 

But Prof Pollard added that the ultimate way to prevent and reduce typhoid infections was investing in better water and sanitation services. 

“It is important to say that what we really need, in addition to vaccines, are more efforts to improve the quality or at least access to high quality water,” he said.

“We know from our own experience with typhoid in 1800s that putting municipal water supply and sanitation prevents typhoid but other serious diarrheal diseases.”

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