Emergency drive finds new vaccine effective against typhoid: experts

An emergency vaccination campaign in Sindh following the outbreak of typhoid in the province has found the typhoid conjugate vaccine to be effective in preventing new cases of the disease, said researchers at an event at the Aga Khan University (AKU).

Over 10,000 cases of extensively drug resistant (XDR) typhoid, a strain of the disease resistant to an unprecedented range of antibiotics, have been reported since 2016 in Karachi and Hyderabad.

This outbreak led to the launch of an emergency vaccination campaign in January 2018 in the worst affected areas of Hyderabad which saw 207,000 children between six months and 10 years of age receive the new vaccine.

At the same time as the campaign, researchers set up a surveillance system in the same area over an 18-month period to screen a cohort of over 20,000 children, who received the vaccine, to detect cases of typhoid. They found that nine out of 10 children in the cohort, or 89 per cent, did not contract the disease.

“The results of the vaccine’s effectiveness are in line with a study in Nepal,” said Dr Farah Qamar, an associate professor in paediatrics and child health at the AKU. “This strengthens the case for the national rollout of the vaccine.”

Dr Farah spoke about how lessons from the Hyderabad campaign had been applied in Karachi’s Lyari neighbourhood, and during the Sindh-wide rollout conducted in November 2018, which aimed to reach over 10 million children during a three-week period. A mop-up campaign is now being planned in Sindh in March 2020 to immunise children between the ages of nine months and 15 years missed during the previous drive. Researchers noted that parents, whose children haven’t receive the vaccine, are keen to participate in the forthcoming immunisation campaign.

Speakers at the event noted that cases of typhoid were being reported in parts of the Punjab province such as Lahore and Multan. The province is yet to launch the vaccine. Punjab EPI Director Dr Muhammad Saeed Akhtar noted that cases of XDR typhoid and multi-drug resistant typhoid had been noticed to date.

“The Punjab government plans to include the vaccine in its routine immunisation programme between September and October 2020,” said Dr Akhtar said. “We will study the lessons learned from the Sindh campaign in order to ensure the success of our drive.”

Dr Anita Zaidi, director of vaccine development, surveillance, and enteric and diarrhoeal diseases at the Bill & Melinda Gates Foundation, expressed her support for efforts to generate evidence of the efficacy for this vaccine against typhoid fever.

She added that a strategy to combat typhoid requires an integrated approach that covers access to clean water, improved sanitation and immunisation. During the event, researchers from the AKU explained how their collaboration with the health authorities in Hyderabad helped trace the cause of the outbreak.

“Our research involved geographic mapping which highlighted how the majority of typhoid cases were reported around sewage lines,” said Dr Momin Kazi, an assistant professor (research) in paediatrics and child health at the AKU. “Household water samples also tested positive for contamination showing that the drinking of contaminated water was the most likely cause for the outbreak.”

The research and policy advocacy efforts supporting the vaccine’s launch were backed by a team at the AKU including Prof Rumina Hasan, Prof Zahra Hasan and Dr Sadia Shakoor from the department of pathology and microbiology, and Dr Farah Qamar, Dr Tahir Yousafzai and Dr Momin Kazi from the department of paediatrics & child health.

The control and prevention of water-borne diseases such as typhoid is a global health priority with targets under goal 3 of the Sustainable Development Goals calling for the eradication of such diseases by 2030.