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Fourteen data loggers were packed with vaccine vials at the national vaccine store, Port Moresby, Papua New Guinea (PNG), and sent to peripheral locations in the health system. The temperatures that the data loggers recorded during their passage along the cold chain indicated that heat damage was unlikely, but that all vials were exposed to freezing temperatures at some time. The commonest place where freezing conditions existed was during transport. The freezing conditions were likely induced by packing the vials too close to the ice packs that were themselves too cold, and with insufficient insulation between them. This situation was rectified and a repeat dispatch of data loggers demonstrated that the system had indeed been rectified. Avoiding freeze damage becomes even more important as the price of freeze-sensitive vaccines increases with the introduction of more multiple-antigen vaccines. This low-cost high-tech method of evaluating the cold chain function is highly recommended for developing and industrialized nations and should be used on a regular basis to check the integrity of the vaccine cold chain. The study highlights the need for technological solutions to avoid vaccine freezing, particularly in hot climate countries.

Without a preservative, such as thiomersal (known as thimerosal in the US), multi-dose liquid presentations of vaccine are vulnerable to bacteriological contamination that can result in death or serious illness of the recipient. Concerns about levels of mercury exposure from thiomersal-containing vaccines were first raised in the US during 1999 in the context of Hepatitis B vaccine for newborns. Since then, a large body of evidence from animal and epidemiological studies has accumulated on the safety of thiomersal. Ironically, these data have become largely irrelevant in wealthy countries, where mono-dose, thiomersal-free vaccines have been introduced as a precautionary measure in almost all childhood vaccines, in part related to residual public scepticism. In poor countries, multi-dose vials remain important for vaccine delivery. There is a real danger that this controversy may result in the loss to the world of thiomersal as a preservative, simply from popular pressure. In reality, it would be impossible to cease overnight using thiomersal and maintain the supply of vital vaccines. This paper reviews and summarises the data available from published studies on mercury toxicity, and thiomersal in vaccines in particular, that overwhelmingly indicate continued use of thiomersal is safe in those countries where it is most needed.

There is an urgent need to change the presentations and delivery technologies of current vaccines. Until recently, these factors had not been key criteria in the selection of vaccines for program use. Recent and current changes in the field of vaccines and their delivery lead the authors to postulate that a major paradigm shift will take place over the next decade to revolutionize vaccine presentation and delivery in national immunization programs. The programmatic needs for certain vaccine presentations will increasingly dictate elements of vaccine development and manufacture. Over the next decade, an inexorable drift towards firstly, single-dose preparations, and secondly, delivery technologies other than the conventional needle and syringes is anticipated. A unified system capable of delivering multiple antigens as a single dose is urgently needed; however, changing the status quo of vaccine manufacture is not easy. The market predominantly produces vaccines delivered by needle and syringe. Profits for manufacturers from sales to developing countries are marginal at best, and there is little financial incentive to change. Global leaders will need to take bold decisions and begin demanding vaccines which have a presentation that lends them to safer, more practical delivery systems. If a strong enough case can be made to restructure the vaccine manufacturing industry, either through market forces, global bodies, such as the World Health Organization and the United Nations Children's Fund, or both, a dramatic change could be brought about that will make vaccine delivery simpler and safer. A globally coordinated approach to funding research and the introduction of a multiple-antigen, single-dose delivery system is urgently needed. The needs are clear, and this review argues that if the case is presented strongly enough, the resources will be found.

While a number of studies remain to be completed, evidence is mounting that there is no demonstrable risk for infants immunized with vaccines containing thiomersal. Epidemiological studies in the US have shown no developmental or other central nervous system abnormalities resulting from exposure to vaccines containing thiomersal. During the initial evaluation of thiomersal in vaccines during 1999, the toxicological profile of ethyl mercury was unknown and presumed to be the same as that of methyl mercury. Enough evidence has accumulated since then to indicate the profiles of the two compounds are different in crucial aspects. To date, one study has measured blood levels of total mercury in vaccinated infants and reports only a brief low-level exposure with rapid excretion of mercury. It is not yet known for sure how much (if any) vaccine-derived ethyl mercury in the blood crosses the blood-brain barrier. For the most part, the use of thiomersal as a vaccine preservative has been convincingly shown to be safe. The scientific evidence is not yet sufficiently strong to provide the same level of assurance for thiomersal-containing vaccines for use in pregnant women or the premature or low birth weight infant. There is an increased sensitivity of the fetal brain to mercury whether it is ethyl or methyl mercury. While there is no evidence to support the contention, it is at least theoretically possible that very low birth weight premature infants may be at increased risk from thiomersal-containing vaccines. Until such time as the scientific evidence is to hand, thiomersal-free presentations of hepatitis B are to be preferred for the birth dose. Given the same levels of exposure, adults are at much lower levels of risk because of increased body mass. It is not possible to prove that thiomersal is completely safe-epidemiology can only quantify a risk, not prove its absence.

There is an ever-expanding technology that is aimed at making the administration of vaccines safer. Conventional ways of administering vaccines are being upgraded, modified or replaced by a wide variety of innovations. The paradigm of liquid vaccines, needles and syringes is slow to change, but already developments are occurring that will change for ever the way vaccines are administered and will improve the safety record of immunization. The oral route of vaccine administration has generally been thought of as safe, but until now only the polio vaccine has been widely used in this way. The conventional method of vaccine administration is by injection. Many ingenious devices have become available that now make injecting safer. Inventors are now looking imaginatively to alternative routes and technologies for delivering vaccines. Vaccines are generally manufactured to extremely high standards and rarely are shown to be the cause of safety issues. People remain the weakest safety link is vaccine administration. Technologies that bypasses the ability of man to make bad decisions or to behave incorrectly are of tremendous value. The vaccine world is in the middle of a radical re-think about how vaccines might best be administered. The presentation of the vaccine can be altered to fit new technologies such as powder jet guns, or skin patches. Even the conventional needle and syringe have evolved to much safer versions, and are set to continue this evolution. All this means even safer vaccines and their delivery.

Abstract: Background: The Expanded Programme on Immunization (EPI), launched in 1974, has developed and implemented a range of strategies and practices over the last three decades to ensure that children and adults receive the vaccines they need to help protect them against vaccine-preventable diseases. Many of these strategies have been implemented, resulting in immunization coverage exceeding 80% among children one year of age in many countries. Yet millions of infants remain under-immunized or unimmunized, particularly in poorer countries. In November 2009, a panel of external experts met at the United States Centers for Disease Control and Prevention (CDC) to review and identify areas of research required to strengthen routine service delivery in developing countries. Methods: Research opportunities were identified utilizing presentations emphasizing existing research, gaps in knowledge and key questions. Panel members prioritized the topics, as did other meeting participants. Findings: Several hundred research topics covering a wide range were identified by the panel members and participants. However there were relatively few topics for which there was a consensus that immediate investment in research is warranted. The panel identified 28 topics as priorities. 18 topics were identified as priorities by at least 50% of non-panel participants; of these, five were also identified as priorities by the panel. Research needs included identifying the best ways to increase coverage with existing vaccines and introduce new vaccines, integrate other services with immunizations, and finance immunization programmes. Interpretation: There is an enormous range of research that could be undertaken to support routine immunization. However, implementation of strategic plans, rather than additional research will have the greatest impact on raising immunization coverage and preventing disease, disability, and death from vaccine-preventable diseases. The panel emphasized the importance of tying operational research to programmatic needs, with a focus on efforts to scale up proven best practices in each country, facilitating the full implementation of immunization strategies. [Copyright &y& Elsevier]

Examines the english language literature on the safety, immunogenecity and effectiveness in children infected with the human immunodeficiency virus of vaccines recommended by World Health Organization (WHO) for use in national immunization programs. Degree of variation in the guideline given bu WHO and general guidelines; Areas of concern that are critical to the development of a medical guideline.

Abstract: Background: At least five different types of viral hepatitis cause problems of significant public health importance in Africa, where together they constitute a huge burden of disease. But until now, efforts to control the infections have been largely piecemeal. Analysis of the strategies needed to control each virus, however, reveals major overlaps. Proposal: We propose that the control of these infections in the WHO African Region should start with the common strategies rather than with each disease. But this approach presents potentially huge problems to overcome, such as the difficulty of integrating multiple health service elements – the track record for successful integration of such services is not good. This is despite encouraging rhetoric from donors and national leaders alike. And to succeed, disparate programmes must work closely together. But we believe that the time is right to create new opportunities for prevention and treatment of hepatitis, including increasing education, and promoting screening and treatment for more than 500 million people already infected with hepatitis B and C viruses. Impact: The impact of these efforts on decreasing mortality and morbidity will be significant because of the high burden of disease from these infections, and also because the effect will spill over to benefit the control of other communicable diseases and health systems strengthening. Such a project will inevitably involve multiple strategies that will vary somewhat according to the epidemiology of the diseases and the location. [Copyright &y& Elsevier]

Abstract: Reaching mothers and their newborn infants around the time of birth with adequate health services has long been a difficult problem in developing countries. In parallel, similar problems have arisen in attempting to deliver hepatitis B (HepB) vaccine to infants born at home in many countries where mother-to-infant transmission is common. It is logical, and supported by experience in Indonesia, to find a combined solution for both problems. The World Health Organization (WHO) recommends that a timely birth dose of HepB vaccine be given, particularly in areas of high vertical transmission of hepatitis B virus (HBV). This can be achieved relatively easily in situations where almost all births occur in health facilities. But where a significant proportion of births occur at home and without birth attendants able to give injections, this is much more difficult. Barriers to the timely administration of the birth dose of HepB vaccine include weakness in policy development and implementation, difficulties in reliably supplying potent vaccine to community level, limited transport, poor communication, limited cold chain capacity, lack of effective training, and lack of a clear delineation of responsibility between health care professionals. Demonstration projects, such as those in Indonesia, suggest that there are significant opportunities to improve the timely delivery of HepB vaccine birth dose in existing maternal and child health programmes where health workers are trained to provide home delivery care. [Copyright &y& Elsevier]