A recent study published in the New England Journal of Medicine has shown that typhoid fever continues to pose a significant public health threat in India, particularly in urban areas. The study, which conducted weekly surveillance for acute febrile illness and measured the incidence of typhoid fever in a prospective cohort of children aged between 6 months and 14 years, found that the incidence of typhoid fever was high in urban areas, with rates ranging from 576 to 1173 cases per 100,000 child-years. In rural Pune, the incidence rate was 35 cases per 100,000 child years.
The study suggests that vaccination may be a more effective way to control the spread of typhoid fever in India, especially in areas where incidence rates remain high. It also highlights that the high incidence of typhoid in urban India suggests that the reported decline in cases from hospitals is due to changes in healthcare-seeking behavior and widespread antibiotic treatment rather than a reduction in transmission.
Typhoid fever is a significant public health concern in India, with more than half of the worldwide cases of the disease projected to have occurred in the country in 2017. The study’s findings highlight the need for continued surveillance and public health interventions to reduce the disease burden in India.
The study also highlights the apparent masking of typhoid disease by the widespread use of effective antibiotics and highlights the significant risk posed by emerging strains of extensively drug-resistant S. typhi. This strengthens the argument for the expanded administration of typhoid conjugate vaccines, which would offer early protection and provide protection in a more extensive vulnerable age range.
According to WHO recommendations, routine immunization with a single dose of a typhoid conjugate vaccine at nine months of age would be a cost-effective way to offer protection, with a one-time catch-up immunization of children up to 15 years of age protecting a more extensive vulnerable age range. However, the geographic heterogeneity of typhoid fever in India complicates immunization programs. While many studies in Africa and Asia show a low incidence of S. typhi in rural areas, others show a relatively high incidence in rural or periurban sites.
The study found that the most commonly administered antibiotics for potential enteric fever were azithromycin and cephalosporins (cefixime or ceftriaxone). The predominant genotype of S. typhi circulating in India (4.3.1, also called H58) remains susceptible to these antibiotics, and all isolates were susceptible to ceftriaxone. However, six S. typhi isolates and eight S. paratyphi A isolates showed evidence of resistance to azithromycin.
The study’s findings have important implications for public health in India. By identifying areas of high incidence, healthcare professionals can target interventions and resources to reduce the spread of the disease and improve patient outcomes. Vaccination may be a more effective way to control the spread of typhoid fever in India, especially in areas where incidence rates remain high, and continued surveillance and public health interventions are needed to reduce the burden of the disease in the country.
