Vanguard of Vaccines

December 19, 2016

 Many decades ago, it would not be terribly unusual to get invited to a chickenpox party. Excuse me?? Yes, parents were happy to have their 5-year-old exposed to the extremely contagious, itchy, red, blistery rash of chickenpox, a disease caused by the varicella zoster virus. The logic was: catch it early and be done with it because it would be so much more dangerous to get it later, as an adult. Now, since 1995 in fact, we have a vaccine for it. Now, such a party would be a NO-NO.

 

Vaccines came into our lives in the late 18th century, when Jenner developed the smallpox vaccine.This was almost a century before the vaccines for rabies, tetanus, typhoid and the bubonic plague were introduced to the public. 20th Century saw rapid development of vaccines for more than 30 diseases. Development of a vaccine, however, does not mean the instant disappearance of that disease: Smallpox was wiped off the face of the earth as late as 1980 (a more potent, heat stable and freeze dried vaccine, introduced in 1971, made all the difference), India was declared polio free in March 2014, and the Americas were rid of measles earlier this year.

Smallpox eradication left a legacy of improved health systems, trained vaccinators, cold chain equipment and a network for surveillance of vaccine preventable diseases. Experts globally agreed to utilize this opportunity and the World Health Organization launched the Expanded Programme on Immunization (EPI) in 1974. Under the EPI, India launched in 1978 the introduction of BCG, OPV, DPT and typhoid-paratyphoid vaccines. Despite the EPI target of at least 80 per cent coverage in infancy, the vaccination was offered through major hospitals and largely restricted to the urban areas and thus the coverage remained low. According to the Rapid Survey on Children (RSOC 2013-14) only 65.3% of the children are ‘fully immunized”, 6.7% not at all, and the rest only partially so. Mission Indradhanush, under the National Health Mission, has set a target of 90% full immunization by 2020, to be sustained there after.

 

 The itinerant nature of MC’s target population makes ‘complete immunization’ for MC Children a bigger challenge. A micro study done by Mobile Creches in 2008, on 425 migrant families with children under six, shows that, 30% of families stayed on a site for a period of six months or less, 38% stayed for one year or more. To start with, when a child arrives at the MC centre, the staff and the doctors have to assess the age of the child (mothers do not always know the exact date of birth) and what shots s/he may have received already. From here on the MC staff maintain health records for each child. When the family moves on they take the card with them and do the follow up at the next stop – their village, another site or another city. MC invites doctors to its sites and also links the parents to the immunization programme at the Primary Health Centres.

 

The vaccination calendar in India is as per the table below.

 

 

Immunization is a critical piece in the public health puzzle but tells only one part ofthe story. Some of the key components of a comprehensive public health program wouldbe as follows:

 

  1. A public health surveillance system to track trends in key health indicators and assess thehealth of the people.

  2. Understandingepidemiology of various diseases; research to fill information gaps.

  3. Articulation and implementation of a public health strategy based on the above.

  4. Dissemination of knowledgefor prevention and treatment.

  5. Documentation of the impact of an intervention and tracking progress towards specified goals.

 

It would be interesting to illustrate, by example, what a public health strategy may look like in the context of one critical indicator of health: infant mortality. In early 20th Century, in the U.S., for instance, efforts to reduce infant mortality focused on improving environmental and living conditions in urban areas: Urban sewage and refuse disposal and safe drinking water played key roles; rising standards of living and education levels helped to promote health; declining fertility rates led to longer spacing of children, smaller family size, and better nutritional status of mothers and infants; milk pasteurization, contributed to the control of milk-borne, gastrointestinal infections.

 

In other words, during the first half of the century, public health, comprehensive maternal and infant welfare services (including prenatal, natal, and postpartum home visits by health-care providers), and clinical medicine (pediatrics and obstetrics) collaborated to combat infant mortality. According to Centre for Disease Control, USA, “The reduction in vaccine-preventable diseases … has reduced infant morbidity and has (only!) had a modest effect on infant mortality.”

 

The experience above underscores the fact that while freedom from diphtheria, tetanus, measles, poliomyelitis, and Haemophilus influenzae type b meningitis, etc., by virtue of tried and tested of vaccinations available today, is the right of every child, that’s not all it takes to ensure the right to health for our communities.The immunization programme, nevertheless, remains a necessary, if not sufficient, part of any public health strategy.

 

While the developed countries have attained good coverage and efficacy of the immunization programme, in the developing world, public health challenges are many: making vaccinations available in a timely manner with guaranteed cold chains and trained staff; prioritizing regular immunization programmes over single disease campaigns; monitoring approval processes and ethical drug trials; addressing societal and cultural issues that relate to illiteracy, religious taboos, superstition, influence of traditional healers, with an overemphasis on curative, rather than preventive, medicine.

 

World vaccine experts propose a number of desirable features for future children's vaccines: single dosage, administered near birth, combined in novel ways, heat stable and affordable.According to Dr. Javed Iqbal and Dr. K. Sreenivas, formerly of Dr Reddy's Laboratories, “Advances in molecular biology and plant biotechnology have opened the door for low-cost technologies usable in developing countries. Recent vaccine ventures using recombinant proteins, non-infectious particles and nucleic acids would have seemed the stuff of science fiction only a short time ago. This revolution promises more effective and clearly targeted vaccines.”

 

See Also :

http://www.iapindia.org/page.php?id=129

http://www.indianpediatrics.net/jan2013/jan-111-118.htm

 

 

 

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