Q. In our opinion, multi-drug resistant typhoid fever is a greater national problem than hepatitis B infection as evidenced by the magnitude of papers presented in conferences and published in Indian Pediatrics and in view of the emergence of multi-drug resistant Salmonella typhi. The necessity for routine immunization and inclusion in the National Immunization Program for these two infections may kindly be contrasted from this perspective. Further, the reported efficacy for all the three typhoid vaccines is equal. However, the important expensive vaccines are allowed to be marketed while Haffkine Institute, Mumbai has stopped manufacturing the indigenous .killed cheap vaccine. We feel that the Indian Academy of ,Pediatrics should take up this issue with the Government.
 

Hemant Joshi,
Archana Joshi,
Joshi Children's Hospital,
Virar, Maharashtra.
 

The World Health Organization has declared hepatitis B vaccine as the 7th EPI Vaccine, to be given to all infants in all countries. The Immunization Committee of lAP has also recommended it for routine immunization of infants of all families who can afford to pay for the vaccine. The Committee and lAP wish that the Ministry of Health of the Government of India will soon approve hepatitis B immunization on the National (Universal) .Immunization Programme. On the other hand, the Immunization Committee has listed typhoid fever immunization as optional; the Government of India does not seem to have an official .policy on it. To make matters worse, the Haffkine Institute at Mumbai has discontinued the manufacture of the classical whole cell typhoid vaccine. The implicit question raised by Drs. Hemant Joshi and Archana Joshi is regarding the relative importance of hepatitis B versus typhoid fever which is a greater national problem? Considering the frequency of typhoid fever as indicated by the large numbers of papers presented in lAP conferences and published in Indian Pediatrics, and in view of the emergence of multi-drug resistant Salmonella typhi, should we not use typhoid immunization more widely? And should we not continue to manufacture and use the whole cell vaccine since it is quite inexpensive, while the newer imported vaccines are very costly? These questions demand our deliberation and clear answers.

We do not have to compare or contrast hepatitis B virus diseases with multi-drug resistant typhoid fever in order to ponder over the problem and prospect of prevention by immunization of typhoid fever; nor need we grade the priorities of these two public health problems in order to highlight the merits of the different typhoid vaccines. These two interventions, hepatitis B immunization and typhoid fever immunization, are not in competition. There is only one way to prevent community-acquired hepatitis B virus infection, both vertical and horizontal, and that is through widespread and routine immunization. We must work to get hepatitis B immunization on our National (Universal) Immunization Programme.

On the other hand, typhoid fever is there suit of poor food and water hygiene and it can be prevented either by good public health action or by immunization. Unlike hepatitis B virus transmission, the spread of Salmonella typhi is not a random process, and there appears to be no justification for routine immunization of all infants (or children) against, typhoid fever. The available information, although very limited, suggests that typhoid fever is' very common in urban slums and in overcrowded town-dwellers, but it is quite uncommon among rural people unless they travel to the town(s). It appears that children ~et typhoid fever in towns, but not in villages. Even in towns and cities, those who live in apartment housing, with piped water supply, and safe disposal of excreta, may not be at much risk of typhoid fever. It is for these reasons that the Immunization Commit- tee recommends that the local epidemiology of typhoid fever must be the guiding principle for using vaccine as a preventive measure. In short, pediatricians must exercise their option to use it and recommend it where the need exists.

Within the context of the background in- formation described above, we must encour- age more liberal' use of typhoid vaccines in our country.. In the geographic communities in which typhoid fever occurs even as low frequency, all children should be offered the vaccine. In addition, health care personnel, workers in commercial food industry and people who travel frequently are logical target groups for typhoid immunization. We have a choice among three safe and effective vaccines against this disease, namely the whole cell killed, the Vi and the oral Ty21 a.

In typhoid endemic communities, particularly (among) the urban poor, children are at risk from the second year onwards, with high incidence by the age of 4 or5 years. Under these circumstances the whole cell killed vaccine is the best suited for two main reasons. First, the vaccine is quite inexpensive and affordable. by even low income families. Second, it can be given to infants and toddlers below 2 years. For these reasons Indian manufactures must continue to' produce and supply it.

The Ministry of Health should instruct the manufacturers to produce killed S. typhi vaccine without adding S. paratyphi A or B. If the vaccine contains only S. typhi, the total number of organisms will be one-third of the TAB vaccine, or one-half of the TA vaccine, thereby reducing the frequency and severity of local and systemic side effects of typhoid immunization. The lAP has an important role to play in this context.

I recommend for further reading the two papers cited below. The first one, published from Vellore, showed that the whole cell killed vaccine induced good antibody response in infants and young children; more- over the response to intradermal inoculation was quite satisfactory(1). Intradermal inoculation causes much less side effects than subcutaneous inoculation; this' route is particularly good for booster inoculations. The second paper is a very recent one, containing a meta-analysis of information on the efficacy and side effects of the three currently available vaccines(2). The authors concluded that "whole cell vaccines are more efficient than the Ty21a and Vi vaccines, but are more frequently associated with adverse events"(2). These adverse events are no worse than the local or systemic reactions to DPT vaccine; they are not serious but short-lived and well tolerated by children and their parents.

Finally, India deserves a transparent and technically competent mechanism to arrive at policy decision concerning the use of old and new vaccines. Most countries rely on an Advisory Committee on Immunization Practice. ln India we do urgently need such a committee, in which experts and representatives of lAP, Indian Council of Medical Research and Health Ministry officials should have the opportunity to consider all issues in detail.
 

T. Jacob John,
Chairman,
lAP Immunization Committee,
Thekkakora, 2/91, Kamalakshipuram.
Vellore 632 002.

 

1. Mohandas V, Cherian T. Sridharan G, Simoes EAF, Pereira SM, John TJ. The immune response of infants and preschool children to typhoid vaccine given intradermally or subcutaneously. Brit Med J 1989; 297: 162-163.

2. Engels EA, Falagas ME, Lau J, Bennish ML. Typhoid fever vaccines: A meta-analysis of studies on efficacy and toxicity. Brit Med J 1998; 316: 110-117.