Typhoid vaccine shots may have an answer for the waterborne disease in India, as clinical trials showed its high effectiveness among 61% people and 80% children.
Typhoid vaccine shots may have an answer for the waterborne disease in India, as clinical trials showed its high effectiveness among 61% people and 80% children.
The vaccine trials were conducted on 37,673 people, including children aged two to five, in Kolkata’s slums. The result was particularly dramatic among children, an age group more prone to disease, who developed better immunity to typhoid.
The study of the trials was published in the New England Journal of Medicine, stating the results may be good news for India, which can eradicate the disease if vaccines are made part of its national public health policies.
Indian Council of Medical Research (ICMR) chief Dr VM Katoch said the vaccines can be used where typhoid is endemic, causing high morality and morbidity. “There have been such trials earlier but the protection rate has not been more than 50%. These trials showed better protection rates and can be very good for temporary use, to contain the endemic in pockets,” Katoch said. He, however, preferred improving water and sanitation conditions to contain the disease.
The clinical trials were conducted by the Seoul-based International Vaccine Institute (IVI) in collaboration with the National Institute of Cholera and Enteric Diseases (NICED) of Kolkata, while ICMR monitored the study’s progress.
The present trials are seen as a big boost to the World Health Organisation’s efforts to eradicate typhoid. The good news is that even All India Institute of Medical Sciences, New Delhi, is developing a Vi conjugate vaccine using the OmpC protein from S typhi as a carrier.
Typhoid fever, a water-borne disease, causes 2,16,000 to 6,00,000 deaths annually in developing nations. Almost 80% of the cases and deaths occur in Asian countries, among which India and Bangladesh probably have the highest number of cases.
Despite the availability of new generation typhoid injectable vaccines known as Vi polysaccharide vaccines, and a WHO recommendation for its use, they are administered sparsely in public health programmes. Antibiotics are usually used to treat typhoid but drug-resistant strains have made it difficult to cure it over the years. In India, typhoid vaccines are optional and are not part of the national immunisation programme. However, some parts of Delhi introduced typhoid vaccination in 2004 for two- to five-year-old children. The vaccine has also been progressively introduced in school-going children vaccination programmes in other Asian countries.
The vaccines’ limited use is partly due to doubts about the programmatic feasibility and effect of Vi vaccination in public health programmes, as well as questions about whether the vaccine is protective in children aged two to five and whether it can confer herd protection.
The vaccines not only prevented infection among immunised people but also among those who came in close contact with the affected, the study claimed. The trials showed that Vi vaccination conferred significant herd protection to non-vaccinees and there were 57% fewer cases of typhoid overall in neighbourhoods.
Protection for children under five was seen to be important as the age group has shown to be at high risk for typhoid fever in many areas where the disease is endemic.
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