[Season of birth and climate as determinants of infant mortality in the mainland part of the Kingdom of Sardinia]

The authors extend earlier work on the impact of climate and culture on child survival in nineteenth-century Italy. They find that "new data for the Kingdom of Sardinia during 1828-37 confirm the preeminence of cultural factors related to child care over pure climatic causes. In the French speaking Savoy, with a continental climate, differences between infant mortality of the winter and of the summer cohorts are very small. In Piedmont, with the same climate, infant mortality of the winter cohort was 35% higher than infant mortality of the summer cohort. In Liguria, with a mild climate because of maritime influence, the differences between winter and summer cohorts are reduced but still evident, Nice being closer to Liguria than to the other French speaking areas." (SUMMARY IN ENG AND FRE)

Strategies for elimination of poliomyelitis in different parts of the world with use of oral poliovirus vaccine

Since its first mass use in 1960, oral polio vaccine ( OPV ) has largely eliminated paralytic poliomyelitis from temperate-climate and subtropical regions of the world that have good health services and a combined total population of almost 2,000 million people. The various strategies used in these countries have been highly successful even where, as in the USA, large numbers of children received no vaccine or only a single dose of OPV . During the period of 1981-1982, only 2.8 cases per 100 million total population per year were reported in the USA. The main challenge in the present era is the economically undeveloped tropical and subtropical regions with inadequate health services that are inhabited by more than half of the world population, where recent surveys for residual paralysis due to poliomyelitis have shown that the incidence of the disease has been higher than it was in the USA and other predominantly temperate-climate countries before the vaccine era. The problem in these countries is that the majority of children receive no vaccine and that the extensive year-round dissemination of virulent polioviruses requires a different strategy of vaccination from that used in the temperate-climate countries. The special point about the annual mass vaccinations with OPV for all children younger than three, four, or five years of age-which have proven highly successful in Cuba (for the past 20 years), in Brazil (during the past three years), and recently also in Mexico-is that all the children are usually vaccinated within one or two days, which quickly breaks the chain of transmission of the virulent viruses, and the annual campaigns create and maintain the maximum number of children with resistant intestinal tracts.

Vaccine control of poliomyelitis in the 1980s

The main challenge of vaccine control of poliomyelitis in the 1980s is in the subtropical and tropical regions of the world where "lameness" surveys in recent years have shown how very high the average annual incidence of paralytic poliomyelitis can be in both rural and urban areas in the absence of epidemics. The procedures by which oral polio vaccine (OPV) rapidly eliminated all or almost all paralytic disease caused by polioviruses from the economically developed temperate climate countries have been inadequate in tropical and subtropical countries, except in some small countries with good health services, largely because there is much more year-round circulation of "wild" polioviruses which continue to produce the disease in the unvaccinated and incompletely vaccinated children. Not even a cheap, hypothetically 100 percent effective, one-dose vaccine could eliminate poliomyelitis in the tropics if, for a variety of reasons, it would reach only a portion of the infant population. Paralytic disease caused by polioviruses has been quickly eliminated from both small and large tropical countries by OPV in well-organized programs of annual mass vaccinations of almost all children under a certain age.