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In a vaccination and laboratory study, two dried smallpox vaccines (designated P and Q) were tested at intervals of 4, 8, 16, and 32 weeks after storage at both 37 degrees C and 45 degrees C. Vaccine P was also tested after 64 weeks at these temperatures and gave 100% successful vaccination rates after all periods of storage at both temperatures. Vaccine Q deteriorated within four weeks, rapidly at 45 degrees C and less rapidly, but very substantially, at 37 degrees C. There was no clear evidence of the cause of this deterioration, but there was a suggestion of denaturation of some of the samples stored at the higher temperature. So far as could be ascertained, the laboratory results-rabbit skin scarification tests and chorio-allantoic membrane pock counts-ran parallel with the vaccination success rates. The pock count was found to be the more accurate method of laboratory titration. Vaccine P as used in the trial was not an exceptional batch.Vaccines which give a pock count of 10(8) infective units per ml will give the highest possible rate of successful primary vaccinations.A statistical note on the trials is given in an annex.

As in an earlier study, the authors have endeavoured to review the world incidence of poliomyelitis on the basis of the available statistical information (official notifications of cases and deaths) and to compare these data with data received from various sources regarding the prevailing viruses.It is certainly not yet possible to establish side by side the cartography of actual poliomyelitis cases and that of the prevalence and distribution of the polioviruses. However, it may not be too early to make a start in this direction.In Africa there was a rise of about 40% in the number of poliomyelitis notifications. Part of this increase is probably due to improved reporting. Characteristic epidemics were observed in the west (Senegal, Cameroons under French administration), as well as in the east (Sudan, Kenya, Tanganyika, Northern and Southern Rhodesia, Union of South Africa).In America the most outstanding outbreaks were observed in Alaska, in Wyoming, Nebraska, Iowa, Florida, and California, and all round the Caribbean Sea (Costa Rica, Guatemala, Haiti, Jamaica, Puerto Rico, Trinidad).In the Asiatic countries the number of notifications was generally of the same order as in 1953.The incidence also declined in Europe, in spite of the fact that Greece was affected by the most serious epidemic recorded in its history. Other outbreaks were recorded in Finland, Switzerland, and Austria, where the incidence had also been high in the previous year. An increase was also noted in Scotland.Finally, in Oceania, poliomyelitis took on epidemic proportions in Australia (in the territory of the Federal Capital and in the States of Victoria and Western Australia) and in the Hawaiian Islands.

In the ten years since attenuated poliovirus was first administered to man for immunization against poliomyelitis, a vast body of experience has grown up and an attempt can now be made to assess the potentialities of oral poliovirus vaccine. The author of this paper seeks to answer two main questions: how safe are the strains now under study, and is oral vaccine effective in practice under the different conditions in which it may be used?From the information gained in large-scale trials involving a total of nearly 70 million people, he concludes that where poliomyelitis is predominantly a disease of infancy and early childhood the vaccines now available are safe both for the individual and for the community. The Sabin strains appear also to be safe for use in areas where the disease affects older children and adults; there is still not enough information to permit final conclusions to be drawn as to the safety of the Koprowski and Lederle strains in such areas.The evaluation of data on the efficacy of rural vaccines is beset with many problems, but the evidence of serological conversion rates suggests that, with one exception, there are no striking differences in efficacy between any of the strains when used in monovalent vaccines. However, 100% conversion cannot be expected in all circumstances from any oral vaccine given once only; repeated administration is clearly necessary, although it is still too early to say what the best vaccine schedule may be in any particular set of circumstances.While the problems yet to be solved are legion, great progress has nevertheless been made in the past decade, and the author looks forward to a steady extension of the use of live poliovirus vaccine and even to the eventual possibility of the eradication of poliomyelitis.

This article describes the evolution of international co-operation for the control of epidemic influenza, from the founding of the United States Armed Forces Commission on Influenza in 1941 to the present network of influenza centres designated by WHO in 42 different countries. The technical problems of dealing with this disease on a worldwide scale are indicated, and their bearing on the development of the WHO influenza programme discussed. Suggestions are made for the simplification and co-ordination of the system on which epidemiological information is compiled, and the need for speed in both its collection and its dissemination is emphasized.

The incidence of poliomyelitis throughout the world is outlined on the basis of official statistics-in many cases necessarily provisional or approximate-augmented by information from wider and unpublished sources. Available reports on the virus types responsible for poliomyelitis outbreaks in recent years are also summarized.A rise in apparent incidence occurred in the following countries in 1953: Africa-Angola, Egypt (largely due to improved reporting), Middle Congo (French Equatorial Africa), Morocco (French Zone), Ruanda-Urundi, Tanganyika, Tunisia, Union of South Africa, and Upper Volta (French West Africa); America-Argentina, Brazil, Canada, Colombia, El Salvador, Greenland, Mexico, Nicaragua, and Uruguay; Europe-Austria, Finland, France, Greece, Italy, Norway, Republic of Ireland, Saarland, Sweden, Switzerland, Trieste (British/United States Zone), Turkey, United Kingdom, and Yugoslavia. The epidemics in Canada and Sweden were the most severe ever recorded in the two countries. The incidence decreased markedly in: Africa-Kenya, Mauritius, Southern Rhodesia, and Uganda; America-Chile (probably), Cuba, and the USA; Asia-Cambodia, Ceylon, India, Israel, Lebanon, Philippines, and Thailand; Europe-Belgium, Denmark, Federal Republic of Germany, Luxembourg, the Netherlands, Portugal, and Spain; Oceania-Gilbert and Ellice Islands, Hawaii Islands, and New Zealand.While data on virus types are insufficient for any definitive conclusions to be reached as to responsibility for poliomyelitis outbreaks, it would appear that all three types are widely distributed, while in the selected areas where polioviruses have been typed, type 1 virus has been isolated the most frequently.

In 1957 the World Health Organization arranged a survey of horse and swine sera in a number of countries in order to gain information on the role and importance of animals in the epidemiology of influenza. The veterinary services of the countries concerned were requested to obtain blood specimens from these animals, if possible both before and after the human pandemic of Asian influenza. This paper reports on the results of haemagglutination-inhibition and complement-fixation tests performed on these sera in WHO Influenza Centres and other collaborating laboratories.It is apparent from these results that the Asian (A2) strain can cause natural inapparent infection in horses and swine. Equine influenza caused by the A-equi strain is also present in many countries from which it had not been previously reported, and infection in pigs with the A-swine strain, long known in the USA, has now been recorded in at least two European countries.In a concluding section, the findings in this survey are related to other observations on the position of animals in influenza epidemiology, and future research needs are outlined.