Expansion of Immunization Menu: New Typhoid Vaccine Added
Experts suggest that a newly recommended conjugate typhoid vaccine could have a significant impact on the 22 million cases and 220,000 deaths from typhoid fever reported each year. Unlike other typhoid vaccines, this vaccine is effective in children, who are at high risk of infection.
Typhoid fever, caused by Salmonella Typhi bacteria, manifests with symptoms such as prolonged fever, headache, nausea, and loss of appetite. The disease can lead to fatal complications in some cases and is highly contagious, spreading through contaminated food or water. It is prevalent in countries with poor sanitation and limited access to clean water, particularly in South Asia and sub-Saharan Africa.
While two typhoid vaccines are already approved to reduce the number of cases, none are licensed for children under two years old. The decision to recommend the new conjugate typhoid vaccine was made by the WHO’s Strategic Advisory Group of Experts on Immunization (Sage), based on its effectiveness demonstrated in clinical trials.
Prof Alejandro Cravioto, the chairman of Sage, emphasized the importance of the vaccine, particularly in light of increasing antibiotic resistance in typhoid bacteria. A recent clinical trial published in The Lancet showed that the vaccine was up to 87% effective, providing strong evidence of its potential impact.
The introduction of the typhoid vaccine into immunization programs poses logistical challenges, especially in African countries, including cost and outreach complexities. However, the development of innovative vaccination techniques, such as a single injection for multiple vaccines, offers promising solutions for more efficient vaccine delivery in the future.
The single-injection approach, currently undergoing research in the USA, utilizes microscopic capsules to store and release vaccine doses at specific intervals. Successful early tests have been conducted in animals, demonstrating the potential for improved vaccine administration and coverage.
