Vaccine innovation, translational research and the management of knowledge accumulation

What does it take to translate research into socially beneficial technologies like vaccines? Current policy that focuses on expanding research or strengthening incentives overlooks how the supply and demand of innovation is mediated by problem-solving processes that generate knowledge which is often fragmented and only locally valid. This paper details some of the conditions that allow fragmented, local knowledge to accumulate through a series of structured steps from the artificial simplicity of the laboratory to the complexity of real world application. Poliomyelitis is used as an illustrative case to highlight the importance of experimental animal models and the extent of co-ordination that can be required if they are missing. Implications for the governance and management of current attempts to produce vaccines for HIV, TB and Malaria are discussed. Article Outlin

Plaque formation and isolation of pure lines with poliomyelitis virus

Plaques have been produced with the three types of poliomyelitis viruses on monolayer tissue cultures of monkey kidney and monkey testis. The number of plaques was proportional to the concentration of the virus. Each plaque originates, therefore, from a single virus particle, defined as the virus unit that is unseparable by dilution. The plaques are due to the specific action of the virus since they are suppressed by type-specific antiserum. Pure virus lines were established by isolating the virus population produced in single plaques. These derived virus lines had the same morphological, serological, and pathogenic properties as the parent strain. High titer virus stocks, with titers up to 7 x 10^8 plaque-forming particles per ml., were obtained

Bibliography on inactivation of viruses and rickettsiae by heat

Inactivation of viruses and rickettsiae by heat - bibliograph

Formation of plaques in chick embryo tissue cultures by the virus of herpes simplex

Thesis (M.A.)--Boston UniversityStudies on the virus of herpes simplex have been done in t he past by using t he embryonated egg and the newborn mouse. Only comparatively recently has attention been directed to the use of the tissue culture method for this purpose. Howe ver, relatively little has been accomplished up to the present time by this method in the quantitative studies of this virus. This can probably be attributed, for the most part, to the lack of adequate and accurate tissue culture techniques. An interesting approach to the development of a more accurate tissue culture technique was made by Dulbecco in 1952, who devised a new tissue culture technique by which he succeeded in obtaining focal necrotic areas (plaques) in chick embryo monolayer tissue cultures by the viruses of Western equine encephalomyelitis and Newcastle Disease. Thus the possibility arose for the study of certain animal viruses along lines similar to the ones used in the related field of bacterial viruses. Using this new technique, Dulbecco and Vogt have recently proved that, indeed, it can be successfully used for as saying poliomyelitis virus. The purpose of this work was to investigate the possibility of applying; this "plaque-production" method to the assay of herpes simplex virus and to simultaneously compare its plaque producing capacity in tissue culture with that on the chorioallantoic membrane of the developing chick embryo. The currently employed techniques were modified for the sake of simplicity and convenience. The tissue cultures were set up as follows, in principle following the techniques devised by Dulbecco and Noyes: Five to six 11-day-old chick embryos were washed in Hanks' balanced salt solution (HBSS) and pressed through a 30-mesh wire screen into 15 ml of HBSS by means of a 50-ml syringe, and this material centrifuged at 800 r.p.m. for 30 seconds. The sediment was resuspended with 15 ml of BBSS and after vigorous pipetting centrifuged at 800 r.p.m. for 20 seconds. The supernatant was removed and allowed to stand for 20 minutes. The sediment of this was discarded and the cell concentration of the suspension determined in a hemocytometer. An appropriate amount of this cell suspension was added to the nutrient medium, which consisted of 40% HBSS (with indicator), 40% unheated horse serum and 20% chick embryo extract in order to give a final concentration of 8 x 10^6 cells per ml, the pH of the suspension being 7.6. 3 ml of this were then introduced into each 50-mm Petri dish, coated with chicken plasma, and the dishes sealed with Parafilm. The cultures were incubated at 37 C for 48 hours and at that time the nutrient medium removed, the cultures washed with HBSS, and 0.1 ml or more of the virus inoculated with a hypodermic syringe, gauge 27 needle, and well distributed all over the cell layer. The virus used was the Z strain of herpes simplex which had undergone 3 tissue culture and subsequently 5 egg passages since isolation from primary sources. Following inoculation the cultures were incubated at 37 C for 45 minutes and then covered with a thin layer of plasma, or agar incorporated in the nutrient medium (baiting a final concentration of 0.75%). If plasma overlay was used, 3 ml of nutrient medium were added per culture. The petri dishes were sealed then and incubated at 37 C. At the time of examination of the cultures they were stained with neutral red in order to facilitate the visualization of the plaques, the nutrient fluid or agar overlay removed, and the plaques counted and examined microscopically. The observations and results were as follows: Soon after incubation the cells settled out and began to grow, forming a continuous monolayer of cells covering the entire bottom of the Petri dish. They also exhibited good metabolic activity. At 48 hours the pH of the nutrient medium was down to 7.0-7.2 and a uniform cell layer had formed consisting mainly of healthy fibroblast-type cells. No satisfactory cell layer could be obtained without use of the plasma undercoating. Following inoculation of the virus, plaques could be already detected in the cell layer after a 48-hour incubation period in all the experiments carried out. They appeared as round to slightly elongated, colorless, necrotic areas standing out in the red background of stained living cells, and had a diameter of 1-2 mm on the third day. Microscopically they appeared as bounded areas of cellular debris and if examined earlier the gradual disintegration of the cells was apparent. No plaques were produced in control cultures without virus or virus inactivated by heat and their number increased with the concentration of the virus. The endpoint for plaque production of the 10-fold dilutions of this virus was at 10^-4. In cultures with undiluted virus all the cells were completely destroyed, while with 10^-1 inoculum, semi-confluent plaques were produced. At dilutions of 10^-2 , 10^-3, and 10^-4 discrete and separated plaques were formed. The discreteness of the plaques was dependent on the presence of plasma or agar overlay. Either one could be efficiently used and there was no difference between them in regard to plaque formation. A comparative study with the developing chick embryo, inoculated on the 11th day on the C A membrane, showed that the number of foci produced on the membrane correlates with the number of foci produced on the cell layer in tissue culture although the titer was approximately 10-fold lower in vitro with this particular herpes simplex specimen. The results of these experiments have shown that the Z strain of herpes simplex virus produces plaques in monolayer chick embryonic tissue cultures and this assumption was based on the facts that - (1) No plaques were formed in cultures where the virus was absent or inactivated by heat, (2) the number of plaques increased in proportion to the concentration of the virus inoculum, and (3) there is a correlation between the number of plaques formed in tissue culture and number of pox produced on the CA membrane of the developing chick embryo. The technique employed throughout the experiments described in this paper includes some modifications of the ones already practiced, which simplify and economize, the procedure and makes it easily adaptable for use in any bacteriological laboratory. Further more detailed work is needed to evaluate the aspects and adequacy of this method for quantitative study of the virus of herpes simplex. If satisfactory, it would seem to offer some advantages over certain others currently used

Deconvolving mutational patterns of poliovirus outbreaks reveals its intrinsic fitness landscape.

Vaccination has essentially eradicated poliovirus. Yet, its mutation rate is higher than that of viruses like HIV, for which no effective vaccine exists. To investigate this, we infer a fitness model for the poliovirus viral protein 1 (vp1), which successfully predicts in vitro fitness measurements. This is achieved by first developing a probabilistic model for the prevalence of vp1 sequences that enables us to isolate and remove data that are subject to strong vaccine-derived biases. The intrinsic fitness constraints derived for vp1, a capsid protein subject to antibody responses, are compared with those of analogous HIV proteins. We find that vp1 evolution is subject to tighter constraints, limiting its ability to evade vaccine-induced immune responses. Our analysis also indicates that circulating poliovirus strains in unimmunized populations serve as a reservoir that can seed outbreaks in spatio-temporally localized sub-optimally immunized populations

Population, sexual and reproductive health, rights and sustainable development: forging a common agenda.

This article suggests that sexual and reproductive health and rights activists seeking to influence the post-2015 international development paradigm must work with sustainable development advocates concerned with a range of issues, including climate change, environmental issues, and food and water security, and that a way of building bridges with these communities is to demonstrate how sexual and reproductive health and rights are relevant for these issues. An understanding of population dynamics, including urbanization and migration, as well as population growth, can help to clarify these links. This article therefore suggests that whether or not sexual and reproductive health and rights activists can overcome resistance to discussing "population", become more knowledgeable about other sustainable development issues, and work with others in those fields to advance the global sustainable development agenda are crucial questions for the coming months. The article also contends that it is possible to care about population dynamics (including ageing and problems faced by countries with a high proportion of young people) and care about human rights at the same time. It expresses concern that, if sexual and reproductive health and rights advocates do not participate in the population dynamics discourse, the field will be left free for those for whom respecting and protecting rights may be less of a priority

Community perceptions of a malaria vaccine in the Kintampo districts of Ghana.

BACKGROUND: Malaria remains the leading cause of morbidity and mortality in sub-Saharan Africa despite tools currently available for its control. Making malaria vaccine available for routine use will be a major hallmark, but its acceptance by community members and health professionals within the health system could pose considerable challenge as has been found with the introduction of polio vaccinations in parts of West Africa. Some of these challenges may not be expected since decisions people make are many a time driven by a complex myriad of perceptions. This paper reports knowledge and perceptions of community members in the Kintampo area of Ghana where malaria vaccine trials have been ongoing as part of the drive for the first-ever licensed malaria vaccine in the near future. METHODS: Both qualitative and quantitative methods were used in the data collection processes. Women and men whose children were or were not involved in the malaria vaccine trial were invited to participate in focus group discussions (FGDs). Respondents, made up of heads of religious groupings in the study area, health care providers, traditional healers and traditional birth attendants, were also invited to participate in in-depth interviews (IDIs). A cross-sectional survey was conducted in communities where the malaria vaccine trial (Mal 047RTS,S) was carried out. In total, 12 FGDs, 15 IDIs and 466 household head interviews were conducted. RESULTS: Knowledge about vaccines was widespread among participants. Respondents would like their children to be vaccinated against all childhood illnesses including malaria. Knowledge of the long existing routine vaccines was relatively high among respondents compared to hepatitis B and Haemophilus influenza type B vaccines that were introduced more recently in 2002. There was no clear religious belief or sociocultural practice that will serve as a possible barrier to the acceptance of a malaria vaccine. CONCLUSION: With the assumption that a malaria vaccine will be as efficacious as other EPI vaccines, community members in Central Ghana will accept and prefer malaria vaccine to malaria drugs as a malaria control tool. Beliefs and cultural practices as barriers to the acceptance of malaria vaccine were virtually unknown in the communities surveyed

Testing regimes in clinical trials: evidence from four polio vaccine trajectories

This paper highlights distinctive features of a neglected class of economic activity in the domain of medical innovation, namely the creation of testing regimes in clinical trials, asking how their nature might be expected to affect innovation of medical technology. It argues firstly that clinical trials are not simply about passively validating an already well-known technology and verifying its safety. Rather, clinical trials are part of a more active process of learning that allows pharmaceutical innovations to be useful outside the laboratory. It argues secondly that product development can proceed along a number of long and costly paths before a product’s behaviour in actual practice becomes clear, which can make selecting between alternative courses of action difficult. Thus, product choice and product development need to go hand-in-hand. To consider these arguments, the paper maps out four trajectories of polio vaccine development, tracing their paths through clinical trials since the 1950s, and describes some of the defining features of testing regimes for medical innovation. These include institutions that integrate knowledge and co-ordinate skills in testing processes, and capabilities for allocating testing resources, managing testability constraints, sharing knowledge and improving commensurability between testing communities