Countries classified by the United Nations as part of the developing world are most in need of vaccines but least able to afford them. This article explains the general requirements for manufacturing new vaccines in the developing world instead of importing them.
For all common devastating childhood diseases — tetanus, diphtheria, pertussis, polio, and measles — worldwide universal coverage has been and remains the goal.1 If vaccines for other diseases, such as mumps, rubella, pneumococcal pneumonia, meningitis, and hepatitis B, were easily available in the required quantities, they too would be targets for universal coverage.
Vaccines are currently in development for three diseases that are major threats to world public health: tuberculosis, malaria, and AIDS. Tuberculosis is re-emerging as a major public health threat with almost 2 billion people infected, 17 million with active disease, and approximately 2 million deaths each year worldwide. Malaria infects approximately 300 million persons, causes over a million deaths (mostly among children under five years of age), and debilitates and destroys the economic effectiveness of many adults throughout the world each year. HIV currently infects 40 million people and approximately 15,000 new infections occur every day. It is important to plan for the production, cost, and distribution of vaccines for the developing world so immunization can begin as soon as possible after vaccines are available.
WHO, multiple non-governmental organizations, and charitable organizations (most notably the Bill and Melinda Gates Foundation) have prioritized the development of vaccines for these diseases.2 The discovery phase of vaccine development receives considerable attention, but to achieve ultimate success, these vaccines must be manufactured and delivered to billions of people.3 This article explores the requirements for manufacturing vaccines for tuberculosis, malaria, and AIDS in the developing world where there are extreme economic constraints and other challenges to biopharmaceutical production.
Figure 1. Proportion of Indian Population Immunized by Year.
COUNTING THE IMMUNIZED
Before we discuss the problems of producing enough vaccine, we must estimate how many people need to be immunized. The following questions are our starting point.
- How do we make enough vaccine to completely immunize a specific age group year after year?
- What immunization rate will maintain or expand the rate of immunization so the entire population susceptible to the disease is covered. What immunization rate can assure that all children are vaccinated by a certain age?
- How can manufacturing plants be designed and built so that they can produce this quantity of vaccine?
- When should construction planning begin so the new vaccine can be launched as soon as it is proven efficacious?
- How much will the construction and operation of these plants cost, and how much will the vaccine cost?
These questions can be answered with a reasonable degree of certainty even before the vaccines have been discovered and the manufacturing processes developed.3 We will examine the process, manufacturing, and distribution requirements for a new vaccine.
Table 1. Comparison of Single-Dose and Multiple-Dose Products.
The population and growth of India provides a model of the eventual production needs for vaccines for tuberculosis, malaria, and AIDS. India has a population of approximately one billion and an annual growth rate of 1.7%. The population will grow to approximately 1.4 billion in 20 years, which is the expected lifetime of a manufacturing plant. A new vaccine-manufacturing plant should be designed and built at the correct size.