POINTS OF VIEW JUN 2015
By - Clarisa B Palatnik de Sousa
Vaccination is the most effective method of preventing infectious diseases and is largely responsible for the worldwide eradication of smallpox and the restriction of diseases such as polio, measles, and tetanus from much of the world.
In USA, where population had access to vaccines and antibiotics, during the first 8 decades of the XX century, the infectious disease mortality rate declined substantially. A total of 797 deaths per 100,000 was recorded in 1900 and only 36 per 100,000 in 1980, consistent with the concept of epidemiological transition from an age of pestilence and famine to an age of degenerative diseases. Pneumonia, Influenza and Tuberculosis were responsible for the largest number of infectious diseases deaths throughout the century. However, the emergence of AIDS and tuberculosis demonstrated that gain against infectious diseases were not definitive. In high-income countries, 70% of deaths are due to chronic diseases, among people aged 70 years and older.
The global burden of tuberculosis remains however enormous in Southeast Asia, Sub-Saharan Africa and Eastern Europe, mainly because of the poor control and high rates of M. tuberculosis and HIV co-infection in some African countries. Every year there are 350–500 million cases of malaria, with 1 million fatalities (90 percent in Africa). In low-income countries, nearly 40% of deaths are among children and only 20% among people aged 70 years and older. People predominantly die of lower respiratory infections, HIV/AIDS, diarrheal diseases, malaria and tuberculosis.
Several important problems impeded us from defeating infectious diseases. Among them, we can consider: 1) vaccine R&D funded at 10% of which goes to research in therapies 10; 2) the increased standards of safety regulations applied to vaccines, that promoted the evolution to recombinant or synthetic vaccines, which are less immunogenic and demand a more sophisticated industrial technology; 3) the lack of vaccines based on universal antigens that will exert cross-protection to the prevalent variables of all continents; 4) the lack of vaccines based on conserved antigens that would not demand annual revaccination and 5) the extensive numbers of Phase II-IIb and Phase III trials required before licensing a vaccine. In addition, due to the recent global economic crisis, vaccine companies of USA and Europe consider interrupting the fabrication of preventive vaccines and showing more interest in the development of therapeutic vaccines or drugs, which are more profitable.
On the other hand, in developing countries such as Brazil, Argentina and others, Public Health programs of vaccinations rely on the partial or complete production of vaccines by non-profitable Public Institutions. Although the government might buy vaccines from foreigner companies, a national immunization program and a plan to achieve self-sufficiency in vaccine production through local institutions exists. The success of control of infectious diseases by vaccinations depends not only on the free distribution of vaccine by the government institutions but also in the obligatory condition of vaccination. In contrast, the non-obligatory condition of anti-rabies canine vaccination in Europe, and the lack of control for anti-rabies vaccination for exported animals allowed the recent detection of canine rabies, in Britain caused by infected dogs being exported from Bulgaria.
The future success in the worldwide control of infectious diseases by preventive vaccination however, might depend on the strengthening of the model adopted by developing countries, which involves the obligatory, gratuitous governmental distribution of vaccines produced by Public Heath non-profit institutions.