New thermostable vaccines can help India overcome current delivery barriers, reduce costs and improve coverage
Many first-generation vaccines have not been developed keeping in mind the specific needs of countries with poor infrastructure for vaccine delivery. There is, thus, a need to explore how to tackle one of the greatest public health and logistics challenges in the developing world — distributing life-saving vaccines without the requirement for large bulk shipments, expensive warehousing and costly, difficult-to-maintain refrigerated shipping paths, from the manufacturing plant to the patient.
India launched its National Immunisation Programme in 1978 with a target coverage rate of 80 per cent. This figure has not been achieved to date, largely because the programme had limited reach, mostly in urban areas, during its inception stage. The programme was changed in 1983 when the typhoid vaccine was dropped and again in 1985 when the measles vaccine was added.
Today, the NIP is known as the the Universal Immunisation Programme. The UIP is aimed at a birth cohort of 26 million infants as well as approximately 100 million children between the ages of one and five years for booster doses of UIP vaccines. By Government estimates, despite considerable efforts, India’s national immunisation coverage for tuberculosis, diphtheria, tetanus, pertussis, polio and measles stands at 61 per cent — well below the original target — while neighbouring Bangladesh and Sri lanka have achieved higher coverage.
To ensure safe and effective vaccination, the UIP established approximately 27,000 cold chain points across the country where vaccines are stored at recommended temperature. BCG, OPV, DPT, Polio and Measles vaccines require refrigerated storage at 2-8°C either in walk-in coolers or ice-lined refrigerators and transportation in cold boxes with ice packs. Polio vaccine must be stored frozen at -20°C.
Once taken out of cold storage, heat sensitive vaccines such as polio vaccine (oral and inactivated), JE vaccine, and measles vaccine can quickly lose potency. Temperature changes can significantly compromise the effectiveness of immunisation, shorten shelf life and hamper the delivery of life-saving vaccines to children in greatest need. In a large, diverse, heterogeneous and poorly-resourced country like India, this can affect vaccine access and delivery particularly in rural areas.
India maintains a five-level supply chain for vaccines. This chain begins with government medical supply depots that are located in Kolkata, Mumbai, Karnal and Chennai. These depots supply State vaccine stores which, in turn, supply to regional vaccine stores. Vaccine is sent from the regional stores to district vaccine stores, which then supply primary or community health centres. The entire cycle of cold storage in GMSDs and distribution in community health centers can take up to a year, incurring significant expense to an already burdened system.
According to a WHO report, India’s GMSDs are old, damaged and in need of urgent repair, and its cold chain and logistics is in dire need of trained manpower. Also missing are computerised systems to record cold chain equipment, spare parts, vaccine inventory, repair and maintenance. It’s unrealistic to expect that these systems can sustain India’s future vaccination needs.
A slightly different approach to cold chain, called the controlled temperature, chain has been successfully tested in Africa. CTC is an approach used to distribute some of the more heat-stable vaccines to remote and difficult-to-access areas for limited periods of time (one to four days), when access to refrigeration and ice is limited. Unlike cold chain, where the vaccine is refrigerated all the way till administration, in CTC, vaccines are taken out into the ambient environment during vaccination campaigns.
Costs associated with cold chain systems and vaccine transportation can be halved by under CTC. As environmental conditions such as high heat and humidity are common with Africa, the CTC approach has potential in India. There are already a number of heat stable vaccines in India’s UIP that could benefit from CTC.
Recent advances in technologies allow development of thermostable vaccines. It is now possible to create formulations that demonstrate many months of stability under ambient temperatures including extreme conditions of 45°C or higher. It is also possible that vaccines could be maintained completely outside of the cold chain, all the way from shipment by the manufacturer to vaccination in the field.
(The writer is CEO of Hilleman laboratories)