Ebola Virus Persistence in Breast Milk After No Reported Illness: A Likely Source of Virus Transmission From Mother to Child

A 9-month-old infant died from Ebola virus (EBOV) disease with unknown epidemiological link. While her parents did not report previous illness, laboratory investigations revealed persisting EBOV RNA in the mother’s breast milk and the father’s seminal fluid. Genomic analysis strongly suggests EBOV transmission to the child through breastfeeding.

Epidemiology of Ebola Virus Disease in the Western Area Region of Sierra Leone, 2014-2015

Introduction

Western Area (WA) of Sierra Leone including the capital, Freetown, experienced an unprecedented outbreak of Ebola from 2014 to 2015. At the onset of the epidemic, there was little information about the epidemiology, transmission dynamics, and risk factors in urban settings as previous outbreaks were limited to rural/semi-rural settings. This study, therefore, aimed to describe the epidemiology of the outbreak and the factors which had most impact on the transmission of the epidemic and whether there were different drivers from those previously described in rural settings.

Methods

We conducted a descriptive epidemiology study in WA, Sierra Leone using secondary data from the National Ebola outbreak database. We also reviewed the Ebola situation reports, response strategy documents, and other useful documents.

Results

A total of 4,955 Ebola cases were identified between June 2014 and November 2015, although there were reports of cases occurring in WA toward end of May. All wards were affected, and Waterloo Area I (Ward 330), the capital city of Western Area Rural District, recorded the highest numbers of cases (580) and deaths (236). Majority of cases (63.4%) and deaths (66.8%) were in WA Urban District (WAU); 44 cases were imported from other provinces. Only 20% of cases had a history of contact with an Ebola case, and more than 30% were death alerts. Equal numbers of males and females were infected, and very few cases (3.2%) were health workers. Overall, transmission was through contact with infected individuals, and intense transmission occurred at the community level. In WAU, transmission was mostly between neighbors and among inhabitants of shared accommodations. The drivers of transmission included high population movement to and from WA, overcrowding, fear and lack of trust in the response, and negative community behaviors. Transmission was mostly through contact and with limited transmission through sex and breast milk.

Conclusion

The unprecedented outbreak in WA was attributed to delayed detection, inadequate preparedness and response, intense population movements, overcrowding, and unresponsive communities. Anticipation, strengthening preparedness for early detection, and swift and effective response remains critical in mitigating a potential urban explosion of similar future outbreaks.

Resurgence of Ebola Virus Disease in Guinea Linked to a Survivor With Virus Persistence in Seminal Fluid for More Than 500 Days

We report on an Ebola virus disease (EVD) survivor who showed Ebola virus in seminal fluid 531 days after onset of disease. The persisting virus was sexually transmitted in February 2016, about 470 days after onset of symptoms, and caused a new cluster of EVD in Guinea and Liberia.

Eradicating polio: today's challenges and tomorrow's legacy

Since its launch in 1988, the Global Polio Eradication Initiative has grown into one of the largest international health efforts in history, operating in every country and area in the world. The burden of polio disease has been reduced by over 99%, and the number of countries with indigenous virus has fallen from more than 125 to just four. As importantly, a strong surveillance and laboratory infrastructure has been established for vaccine-preventable diseases (including measles, tetanus, yellow fever, rubella and Japanese encephalitis), and a massive investment has been made in the physical infrastructure and human resources needed to deliver routine immunizations and other health services in developing countries. Between 2000 and 2003, new challenges to polio eradication emerged, threatening the interruption of the transmission of wild poliovirus globally and the eventual elimination of any residual polio disease as the result of the continued use of oral polio vaccines. By the end of 2005, a range of solutions had been developed to address these late challenges, including two new monovalent oral polio vaccines, new and robust international standards for the response to polio outbreaks, and renewed political commitment across the countries that remain infected. As importantly, a comprehensive strategy had been established for managing the long-term risks of paralytic polio, centred, ironically, on the eventual elimination from routine immunizations of the vaccine that is still central to the success of the global eradication effort.

Mass vaccination: when and why

With increased demand for smallpox vaccination during the nineteenth century, vaccination days--early mass vaccination campaigns--were conducted over time-limited periods to rapidly and efficiently protect maximum numbers of susceptible persons. Two centuries later, the challenge to rapidly and efficiently protect populations by mass vaccintion continues, despite the strengthening of routine immunization services in many countries through the Expanded Programme on Immunization strategies and GAVI support. Perhaps the most widely accepted reason for mass vaccination is to rapidly increase population (herd) immunity in the setting of an existing or potential outbreak, thereby limiting the morbidity and mortality that might result, especially when there has been no routine vaccination, or because populations have been displaced and routine immunization services disrupted. A second important use of mass vaccination is to accelerate disease control to rapidly increase coverage with a new vaccine at the time of its introduction into routine immunization programmes, and to attain the herd immunity levels required to meet international targets for eradication and mortality reduction. In the twenty-first century, mass vaccination and routine immunization remain a necessary alliance for attaining both national and international goals in the control of vaccine preventable disease.

Protecting investments in polio eradication: the past, present and future of surveillance for acute flaccid paralysis

In September 2003 a WHO consultation group on vaccine-derived polioviruses (VDPV) concluded that in order to prevent future generations of paralytic polio after interruption of transmission of wild poliovirus, the use of trivalent oral polio vaccine (OPV) must be stopped [1]. Another important global policy decision along the road to polio eradication thus became possible – cessation of OPV use at some time after eradication. The question now is not whether OPV must be stopped, but rather when.

Possible global strategies for stopping polio vaccination and how they could be harmonized

One of the challenges of the polio eradication initiative over the next few years will be the formulation of an optimal strategy for stopping poliovirus vaccination after global certification of polio eradication has been accomplished. This strategy must maximize the benefits and minimize the risks. A number of strategies are currently under consideration, including: (i) synchronized global discontinuation of use of oral poliovirus vaccine (OPV); (ii) regional or subregional coordinated OPV discontinuation; and (iii) moving from trivalent to bivalent or monovalent OPV. Other options include moving from OPV to global use of IPV for an interim period before cessation of IPV use (to eliminate circulation of vaccine-derived poliovirus, if necessary) or development of new OPV strains that are not transmissible. Each of these strategies is associated with specific advantages (financial benefits for OPV discontinuation) and disadvantages (cost of switch to IPV) and inherent uncertainties (risk of continued poliovirus circulation in certain populations or prolonged virus replication in immunodeficient persons). An ambitious research agenda addresses the remaining questions and issues. Nevertheless, several generalities are already clear. Unprecedented collaboration between countries, regions, and indeed the entire world will be required to implement a global OPV discontinuation strategy Regulatory approval will be needed for an interim bivalent OPV or for monovalent OPV in many countries. Manufacturers will need sufficient lead time to produce sufficient quantities of IPV Finally, the financial implications for any of these strategies need to be considered. Whatever strategy is followed it will be necessary to stockpile supplies of a poliovirus-containing vaccine (most probably all three types of monovalent OPV), and to develop contingency plans to respond should an outbreak of polio occur after stopping vaccination.

Progress towards global polio eradication

Twelve years after the global polio eradication goal was set, polio cases have declined by more than 95% world-wide. Polio immunization campaigns have been conducted in every endemic country with as many as 470 million children immunized per year. Intense wild poliovirus transmission is now limited to South Asia and sub-Saharan Africa. To achieve eradication at the earliest possible date, immunization campaigns are being intensified in the remaining endemic countries. Major programmatic challenges include reaching vulnerable children in areas with armed conflict and ensuring full financial and political support for the initiative. With global eradication imminent, WHO is preparing for post-eradication issues: containment of polioviruses, certification of eradication, and stopping immunization.

Poliomyelitis eradication: progress, challenges for the end game, and preparation for the post-eradication era

In 1988, the World Health Assembly resolved to eradicate poliomyelitis globally by the year 2000. Dramatic progress toward this goal has occurred: three of the six WHO regions (Region of the Americas, European Region, and Western Pacific Region) are now polio free; and the number of polio-endemic countries decreased from over 125 in 1988 to 30 in 1999. Intensified efforts currently are underway to reach the target as soon as possible after 2000 in the three remaining polio-endemic WHO regions (African Region, Eastern Mediterranean Region, and South-East Asia Region). Even in polio-endemic regions, many countries are already polio free as the geographic extent of poliovirus shrinks while others. especially those experiencing conflict and war, pose substantial challenges to implementing the proven polio eradication strategies. Increasing attention and research now are devoted to the certification of polio eradication in the polio-free regions (that will include the first phase of implementing the Global Plan of Action for the laboratory containment of wild poliovirus) and formulating a policy for stopping all polio vaccination once eradication, containment, and global certification have been achieved. This report outlines the progress toward polio eradication and highlights some of the remaining issues and challenges that must be addressed before polio becomes a disease that future generations know only by history.

Eradication of poliomyelitis in countries affected by conflict

The global initiative to eradicate poliomyelitis is focusing on a small number of countries in Africa (Angola, Democratic Republic of the Congo, Liberia, Sierra Leone, Somalia, Sudan) and Asia (Afghanistan, Tajikistan), where progress has been hindered by armed conflict. In these countries the disintegration of health systems and difficulties of access are major obstacles to the immunization and surveillance strategies necessary for polio eradication. In such circumstances, eradication requires special endeavours, such as the negotiation of ceasefires and truces and the winning of increased direct involvement by communities. Transmission of poliovirus was interrupted during conflicts in Cambodia, Colombia, El Salvador, Peru, the Philippines, and Sri Lanka. Efforts to achieve eradication in areas of conflict have led to extra health benefits: equity in access to immunization, brought about because every child has to be reached; the revitalization and strengthening of routine immunization services through additional externally provided resources; and the establishment of disease surveillance systems. The goal of polio eradication by the end of 2000 remains attainable if supplementary immunization and surveillance can be accelerated in countries affected by conflict.

Disease eradication as a public health strategy: a case study of poliomyelitis eradication

Disease eradication as a public health strategy was discussed at international meetings in 1997 and 1998. In this article, the ongoing poliomyelitis eradication initiative is examined using the criteria for evaluating candidate diseases for eradication proposed at these meetings, which covered costs and benefits, biological determinants of eradicability (technical feasibility) and societal and political considerations (operational feasibility). The benefits of poliomyelitis eradication are shown to include a substantial investment in health services delivery, the elimination of a major cause of disability, and far-reaching intangible effects, such as establishment of a "culture of prevention". The costs are found to be financial and finite, despite some disturbances to the delivery of other health services. The "technical" feasibility of poliomyelitis eradication is seen in the absence of a non-human reservoir and the presence of both an effective intervention and delivery strategy (oral poliovirus vaccine and national immunization days) and a sensitive and specific diagnostic tool (viral culture of specimens from acute flaccid paralysis cases). The certification of poliomyelitis eradication in the Americas in 1994 and interruption of endemic transmission in the Western Pacific since March 1997 confirm the operational feasibility of this goal. When the humanitarian, economic and consequent benefits of this initiative are measured against the costs, a strong argument is made for eradication as a valuable disease control strategy.

Poliomyelitis eradication

Since the poliomyelitis eradication program began in 1988, the number of poliovirus infected continents and countries have decreased from five to two and from greater than 100 to 53, respectively. A nearly 90% reduction in the incidence of polio has been achieved with a corresponding decrease in virus genomic heterogeneity. Major challenges to eradication remain in south Asia and Africa in those areas with hot and humid climates, high population density, and high birth rates. Of particular concern are countries with ongoing social unrest and poor health infrastructure. With the approaching eradication of polio, post-eradication issues are now being addressed. The World Health Organization (WHO) draft plan for containment of wild polioviruses has been published for comment. Commissions and committees for certification of eradication have been established. Still under discussion is the question of the appropriate strategy for stopping oral polio vaccine (OPV) immunization. Studies are underway to determine whether vaccine-derived polioviruses will continue to circulate after OPV cessation and the potential disease consequences of that circulation.

Certifying the elimination of poliomyelitis from Europe: advancing towards global eradication

Indigenous wild polioviruses have been virtually eliminated from the 51 countries of the European Region of the World Health Organization (WHO), an achievement that is of critical importance to the global initiative to eradicate poliomyelitis by the year 2000. An international commission has been established to certify the elimination of poliomyelitis from this region. European countries have recently been requested to establish National Certification Committees to review and submit the necessary documentation and surveillance data. In some Western European countries where polio has not been reported for many years, the challenge will be to produce robust evidence demonstrating both the current absence of wild poliovirus and the means to promptly detect and respond to possible importations of wild poliovirus for the next several years, up to global eradication and the cessation of polio vaccination.

KEY MESSAGES

1. laboratory-based surveillance with collection of faecal specimens is necessary to demonstrate the absence of indigenous wild poliovirus 2. certification can only occur after all countries have demonstrated the absence of indigenous wild polioviruses for at least 3 years and have the means to detect and respond to importations of wild poliovirus for several years into the future 3. any single case of poliomyelitis in Europe now requires an immediate public health response which includes virological investigation and prompt notification to the World Health Organization.

Disease eradication as a public health strategy: is measles next?

Following the failure of disease eradication efforts in the first half of this century, the success of smallpox eradication and the ongoing initiatives against poliomyelitis and dracunculiasis are re-establishing eradication as a viable disease control strategy. The perpetual benefits of eradication, together with the positive impact that such initiatives can have on health services in general, are changing the world's perception of these endeavours. Among the most obvious examples of this changing trend is the recent enthusiasm in both industrialized and developing countries for re-exploring the eradicability of measles. Increasingly, it appears that measles, the single leading cause of vaccine-preventable childhood morbidity and mortality worldwide, may be the next major organism targeted for global eradication.

Outbreak of paralytic poliomyelitis in Albania, 1996: high attack rate among adults and apparent interruption of transmission following nationwide mass vaccination

After >10 years without detection of any cases of wild virus-associated poliomyelitis, a large outbreak of poliomyelitis occurred in Albania in 1996. A total of 138 paralytic cases occurred, of which 16 (12%) were fatal. The outbreak was due to wild poliovirus type 1, isolated from 69 cases. An attack rate of 10 per 100,000 population was observed among adults aged 19-25 years who were born during a time of declining wild poliovirus circulation and had been vaccinated with two doses of monovalent oral poliovirus vaccines (OPVs) that may have been exposed to ambient temperatures for prolonged periods. Control of the epidemic was achieved by two rounds of mass vaccination with trivalent oral poliovirus vaccine targeted to persons aged 0-50 years. This outbreak underscores the ongoing threat of importation of wild poliovirus into European countries, the importance of delivering potent vaccine through an adequate cold chain, and the effectiveness of national OPV mass vaccination campaigns for outbreak control.

Perspectives from the global poliomyelitis eradication initiative

Ten years after the year 2000 target was set by the World Health Assembly, the global poliomyelitis eradication effort has made significant progress towards that goal. The success of the initiative is built on political commitment within the endemic countries. A partnership of international organizations and donor countries works to support the work of the countries. Interagency coordinating committees are used to ensure that all country needs are met and to avoid duplication of donor effort. Private sector support has greatly expanded the resources available at both the national and international level. At the programmatic level, rapid implementation of surveillance is the key to success, but the difficulty of building effective surveillance programmes is often underestimated. Mass immunization campaigns must be carefully planned with resources mobilized well in advance. Programme strategies should be simple, clear and concise. While improvements in strategy and technology should be continuously sought, changes should be introduced only after careful consideration. Careful consideration should be given in the planning phases of a disease control initiative on how the initiative can be used to support other health initiatives.

Ending polio immunization

The World Health (WHO) has implemented a plan to eradicate poliovirus that is widely viewed as having made enormous progress. If all goes as planned, polio will be eradicated on this planet by the year 2003. However, there is a debate, as highlighted in a pair of Policy Forums in this issue, over when vaccination against polio can be stopped. Dove and Racaniello believe that the reliance of the WHO on the live Sabin oral polio virus vaccine (OPV) means that there will be a continuing threat of release of potentially pathogenic virus into the environment. They are also concerned that the planned destruction of all wild-type polio stocks will not be possible. They recommend a switch to the inactivated polio vaccine. In response, Hull and Aylward set out the reasons for thinking that a switch from the OPV is not necessary and describe the studies being sponsored by the WHO to determine how and when immunization can safely be ended.

The impact of immunization control activities on measles outbreaks in middle and low income countries

BACKGROUND

The World Health Organization recommended strategy for responding to measles outbreaks in developing countries does not promote the use of immunization campaigns due to their high cost, disruptive nature and limited impact. Given the substantial morbidity and mortality associated with such outbreaks, a literature review was conducted as a basis for re-evaluating this policy.

METHODS

Reports of supplementary immunization activities that were performed to control measles outbreaks in middle or low income countries were identified. The impact of the immunization activities on the course of each outbreak was evaluated by examining the data provided.

RESULTS

Of 66 reports detailing a measles outbreak in a middle or low income country, 17 described supplementary immunization activities which included seven 'non-selective' immunization campaigns, three 'selective' campaigns and one use of an early 2-dose schedule. Eight of the reports commented on the impact of the response, five of which reported a reduction in outbreak morbidity. Only one of the reports, from an isolated island outbreak, provided sufficient data to support a possible reduction in outbreak-associated morbidity.

CONCLUSIONS

There are limited data on the impact of measles outbreak immunization activities from developing countries. The available data do not support a change in the WHO recommended strategy for conducting a limited, if any, immunization response to such outbreaks. Immunization strategies which aim to prevent outbreaks may be more effective than campaigns to interrupt transmission of an outbreak which has already begun.

Strengthening routine immunization services in the Western Pacific through the eradication of poliomyelitis

Infant immunization coverage in the Western Pacific Region of the World Health Organization was reviewed to evaluate the impact of polio eradication activities on routine immunization services. The trend in bacille Calmette-Guérin (one dose; BCG), diphtheria-tetanus toxoids-pertussis (three doses; DTP3), and measles (one dose) vaccination rates was analyzed from the beginning of eradication activities in 1990 to 1994 in the five polio-endemic countries that conducted supplementary oral polio vaccine immunization. In China and the Philippines, coverage for each antigen remained at or above 90% and 85%, respectively, while in Vietnam, coverage for all three antigens rose from 85% to 95%. BCG, DTP3, and measles vaccine coverage more than doubled in the People's Democratic Republic of Lao and increased by >30% in the Kingdom of Cambodia during the same period.

Development and coordination of the Polio Laboratory Network in the Western Pacific Region of the World Health Organization

A multitiered network of polio laboratories, consisting of specialized reference laboratories, regional reference laboratories, national laboratories and, in the case of China, provincial laboratories, was established in the Western Pacific Region of the World Health Organization (WHO) in 1992. The network currently consists of 43 laboratories within the Region and is coordinated through the WHO Regional Office in Manila. As the levels and extent of supplementary immunization and acute flaccid paralysis surveillance activities have increased, so has the work load of network laboratories. The total number of stool specimens collected and processed in Polio Laboratory Network laboratories in this WHO region in 1995 exceeded 15,000. With the Region now establishing the criteria necessary for certification of polio-free status, it is essential for the Polio Laboratory Network to establish international confidence in its ability to carry out its role in the eradication of polio.

The eradication of poliomyelitis in Egypt: critical factors affecting progress to date

Poliomyelitis eradication activities in Egypt were reviewed to identify the critical factors for the progress seen by 1995 and to highlight problems that could be avoided in other countries in which poliomyelitis is endemic. National immunization and surveillance data demonstrate that the combination of high routine immunization coverage (>85%) with oral polio vaccine combined with two properly conducted rounds of national immunization days (NIDs) resulted in a 75% reduction in reported polio cases between 1992 and 1993. Available data suggest that earlier control strategies, such as single-round NIDs in 1990 and 1991, the administration of inactivated poliovirus vaccine (IPV) at 2 months of age in 1992-1993, and the use of "mop-up" campaigns while wild poliovirus was still widespread, did not contribute substantially to the recent decline in cases. Proper implementation of the World Health Organization's recommended strategies can eliminate wild poliovirus circulation in the large, densely populated tropical countries in which poliomyelitis remains endemic.

Poliomyelitis eradication in the Western Pacific Region

Polio eradication activities in the Western Pacific Region (WPR) have reduced the transmission of wild poliovirus to one remaining focus of endemic transmission in the Mekong Delta area of South Vietnam and Cambodia. There has been a high level of government commitment for national immunization days in all WPR countries in which poliomyelitis was previously endemic and for continuous improvement in acute flaccid paralysis (AFP) surveillance quality. The total number of reported confirmed poliomyelitis cases in 1995 (as of June 1996) was 432, only 7% of the total of 5825 cases reported in 1990. In 1995, wild poliovirus was isolated from only 19 of 4800 AFP patients from whom specimens were collected and analyzed. There has been one importation of wild poliovirus type 1 into China from a neighboring country. An international Regional Commission for the Certification of Poliomyelitis Eradication in the WPR has been formed and met for the first time in April 1996.

The experience of countries in the Western Pacific Region in conducting national immunization days for poliomyelitis eradication

Experience with national immunization days (NIDs) in six countries of the Western Pacific Region has shown that political support at all levels, detailed logistics plans, strategies appropriate to the local situation, and simple social mobilization messages have been key factors in the success of NIDs. Conventional strategies that may apply to conducting routine Expanded Programme on Immunization vaccinations do not necessarily apply to NIDs, in which the maximum number of children must be immunized in 1 or 2 days. Setting up temporary immunization posts at sites convenient to the local situation, moving the posts once or twice during the course of a day, and using volunteers to staff them are among many of the adaptations used successfully. Coverage figures published immediately after an NID can be misleading because of uncertainty about the true denominator. The true measure of the success of NIDs is in surveillance for wild poliovirus after the event.

Integrated disease control initiatives: polio eradication and neonatal tetanus elimination in Egypt

Accelerated disease control initiatives, such as polio eradication by the year 2000, may substantially benefit public health programs in general. In Egypt, the control of other vaccine-preventable diseases, most noticeably neonatal tetanus (NT), has been facilitated by the polio eradication initiative. Linking NT reporting with the acute flaccid paralysis (AFP) surveillance system, which had been established for polio eradication, markedly improved the capacity to identify NT high-risk areas and target supplementary immunization activities appropriately. While the close integration of surveillance activities was to the benefit of both programs, mass immunization activities were not conducted simultaneously because of differences in the objectives, target populations, and operational aspects of oral polio vaccine and tetanus toxoid campaigns. In addition to substantial progress toward polio eradication in Egypt since 1988, there has been an 80% reduction in annual NT cases, in part due to the integration of appropriate aspects of these two disease control initiatives.

Establishing acute flaccid paralysis surveillance under difficult circumstances: lessons learned in Cambodia

The implementation of the World Health Organization's recommended strategies for polio eradication, particularly acute flaccid paralysis (AFP) surveillance, can be limited by difficult circumstances beyond the control of immunization personnel. In Cambodia, however, obstacles to establishing AFP surveillance were rapidly overcome using a strategy that improved reporting through active surveillance in a geographically limited area before gradually expanding to include the whole country. The success of the strategy was ensured by the timely provision of the resources that were needed to establish, expand, and monitor surveillance activities.

National immunization days: state of the art

National immunization days (NIDs) are nationwide mass campaigns to deliver supplemental doses of oral poliovirus vaccine to interrupt the circulation of wild polioviruses. They constitute one of the critical strategies for global poliomyelitis eradication and should be implemented in all countries with widespread poliovirus transmission. The certification of wild poliovirus eradication from the Western Hemisphere in September 1994 verified the effectiveness of this aspect of the World Health Organization's (WHO) overall strategy for polio eradication by the year 2000. NIDs require careful advanced planning and orchestration by each country. WHO provides specific guidelines for NIDs regarding the season, target age group, duration, frequency, inclusion of other interventions, vaccine delivery strategies, and evaluation. With strong routine immunization programs and the effective implementation of NIDs, "mop-up" campaigns, and acute flaccid paralysis surveillance, the goal of global polio eradication will be achieved.

Unimmunized Gypsy populations and implications for the eradication of poliomyelitis in Europe

The certification of poliomyelitis eradication in Europe will eventually require that countries demonstrate there is a minimal risk of wild poliovirus reintroduction and sustained transmission through unimmunized subpopulations such as ethnic minorities. A serologic survey among a Gypsy community in Italy found that despite only 26% documented immunization coverage, serum neutralizing antibodies to poliovirus types 1, 2, and 3 were detected in 81%, 94%, and 63% of the 86 persons studied. While the high level of immunity found in this community may have been due to secondary spread of vaccine virus, the possibility of unrecognized circulation of wild polioviruses cannot be excluded. Targeted immunization of such groups may be the most efficient means of eliminating the risk of importation-associated outbreaks.

The role of surveillance in a 'high risk' approach to the elimination of neonatal tetanus in Egypt

BACKGROUND

Despite an international resolution to eliminate neonatal tetanus (NT) as a public health problem by the year 1995, 490000 cases occurred worldwide in 1994. An analysis of the NT elimination programme in Egypt was conducted to determine the utility of a 'high risk' approach in controlling this disease.

METHODS

Three of the indicators for identifying districts at high risk of NT were evaluated. NT rates, tetanus toxoid coverage (TT2+), and urban or rural status. The reduction in NT incidence from 1992 to 1994 was compared between those high risk districts (> or = 1 NT case/1000 live births in 1992) which did or did not conduct supplementary immunization (P = 0.035).

RESULTS

In a multivariate analysis, the strongest indicator of the NT risk in a district was the presence of > or = 1 case/1000 live births in the previous year (Rate ratios [RR] = 3.34 in 1993 and 3.07 in 1994, P < 0.001). The TT2+ coverage was not a reliable indicator of NT risk. Urban areas had a significantly lower risk than rural areas (RR = 0.62) in 1993 and 0.49 in 1994, P < 0.001). The decline in NT rates was greatest in the 'high risk' districts that conducted supplementary immunization in both 1993 and 1994.

CONCLUSIONS

Although tetanus toxoid immunization of pregnant women will protect newborns from NT, TT2+ coverage calculated by the administrative method may not reflect a population's risk of NT. Surveillance data, however, can be used to identify areas where the ongoing risk NT is high. Conducting supplementary immunization in areas that are identified as 'high risk' on the basis of previous NT rates can significantly reduce the number of cases in subsequent years.

Tetanus: a rare but preventable cause of mortality among drug users and the elderly

Forty deaths due to tetanus were reported in Lazio, Italy, during 1985-1994. Retired persons accounted for 48% of all deaths. Intravenous drug use was the most commonly identified risk factor among individuals aged less than 40 years. The frequent utilization of curative health services by drug users and the elderly should be used as an opportunity to update their immunization status.

Validation of the proposed World Health Organization staging system for disease and infection in a cohort of intravenous drug users

OBJECTIVE

To assess the prognostic utility of the clinical criteria of the World Health Organization's (WHO) proposed staging system for HIV disease and infection in a cohort of intravenous drug users (IVDU) from the ALIVE study.

METHODS

All study subjects known to be HIV-seropositive were included in this analysis. Subjects were classified as WHO clinical stage 1, 2, or 3 at their initial seropositive evaluation. Product-limit estimates and Cox proportional hazard models were used to compare time of progression to AIDS (stage 4) for the first three clinical stages.

RESULTS

Of the original cohort of 2921 IVDU in the ALIVE study, 694 were known to be HIV-positive by January 1992. At the time of their index visit, 49% of the cohort were WHO clinical stage 1, 10% stage 2 and 41% were stage 3. Demographic characteristics of the three groups were similar. Product-limit estimates for progression to AIDS over a 3-year period were 6.5% (SE, 1.5%), 10.4% (SE, 4.1%) and 17.1% (SE, 2.5%) for clinical stages 1, 2, and 3, respectively (log-rank P = 0.003). In a proportional hazards model adjusting for race, age, sex and injection status within 6 months prior to enrollment, the hazard for progression to AIDS was 1.51 [95% confidence interval (CI), 0.60-3.77] and 2.39 (95% CI, 1.40-4.08) for stages 2 and 3, respectively, relative to stage 1.

CONCLUSION

This study, in a population of IVDU, supports the utility of the WHO staging system in predicting progression from HIV seropositivity to AIDS on the basis of clinical signs and symptoms.

Ribavirin therapy of adult respiratory syncytial virus pneumonitis

Respiratory syncytial virus is a common respiratory tract pathogen in infants. Pulmonary infection in adult and elderly populations can occur with severe and even fatal pneumonitis having been reported in several recent outbreaks. We present a previously healthy adult patient who developed respiratory syncytial virus pneumonia severe enough to require mechanical ventilation. Antiviral therapy with aerosolized ribavirin was successfully undertaken and the patient recovered completely. Respiratory syncytial virus infection should be considered in the differential diagnosis of atypical adult pneumonias. Aerosolized ribavirin therapy may be beneficial in treatment.