Unacceptably high mortality related to measles epidemics in Niger, Nigeria, and Chad.

BACKGROUND: Despite the comprehensive World Health Organization (WHO)/United Nations Children's Fund (UNICEF) measles mortality-reduction strategy and the Measles Initiative, a partnership of international organizations supporting measles mortality reduction in Africa, certain high-burden countries continue to face recurrent epidemics. To our knowledge, few recent studies have documented measles mortality in sub-Saharan Africa. The objective of our study was to investigate measles mortality in three recent epidemics in Niamey (Niger), N'Djamena (Chad), and Adamawa State (Nigeria). METHODS AND FINDINGS: We conducted three exhaustive household retrospective mortality surveys in one neighbourhood of each of the three affected areas: Boukoki, Niamey, Niger (April 2004, n = 26,795); Moursal, N'Djamena, Chad (June 2005, n = 21,812); and Dong District, Adamawa State, Nigeria (April 2005, n = 16,249), where n is the total surveyed population in each of the respective areas. Study populations included all persons resident for at least 2 wk prior to the study, a duration encompassing the measles incubation period. Heads of households provided information on measles cases, clinical outcomes up to 30 d after rash onset, and health-seeking behaviour during the epidemic. Measles cases and deaths were ascertained using standard WHO surveillance-case definitions. Our main outcome measures were measles attack rates (ARs) and case fatality ratios (CFRs) by age group, and descriptions of measles complications and health-seeking behaviour. Measles ARs were the highest in children under 5 y old (under 5 y): 17.1% in Boukoki, 17.2% in Moursal, and 24.3% in Dong District. CFRs in under 5-y-olds were 4.6%, 4.0%, and 10.8% in Boukoki, Moursal, and Dong District, respectively. In all sites, more than half of measles cases in children aged under 5 y experienced acute respiratory infection and/or diarrhoea in the 30 d following rash onset. Of measles cases, it was reported that 85.7% (979/1,142) of patients visited a health-care facility within 30 d after rash onset in Boukoki, 73.5% (519/706) in Moursal, and 52.8% (603/1,142) in Dong District. CONCLUSIONS: Children in these countries still face unacceptably high mortality from a completely preventable disease. While the successes of measles mortality-reduction strategies and progress observed in measles control in other countries of the region are laudable and evident, they should not overshadow the need for intensive efforts in countries that have just begun implementation of the WHO/UNICEF comprehensive strategy.

Review of regional measles surveillance data in the Americas, 1996-99.

BACKGROUND: In 1994, ministers of health of countries of North and South America established the goal of measles eradication from the western hemisphere by 2000. To accomplish this goal, the Pan American Health Organization (PAHO) developed an enhanced measles vaccination strategy. METHODS: PAHO's measles eradication vaccination strategy has evolved into three principal components; a catch-up measles vaccination campaign, maintenance of high vaccination coverage (keep-up), and periodic follow-up measles vaccination campaigns. To monitor progress towards measles eradication, measles surveillance has been strengthened, including the laboratory investigation of suspected measles cases. FINDINGS: Both the catch-up and follow-up mass campaigns achieved high vaccination coverages in the respective targeted age groups. In 1996, only 2109 confirmed measles cases were reported in the Americas. In 1997, there was a resurgence of measles in the Americas, mostly as a result of a large measles outbreak with over 42000 cases, which occurred mainly among unvaccinated young adults in Sao Paulo State, Brazil. By 1998, there was a reduction in the number of reported confirmed measles cases, with a total of 14474 cases. Reduction of cases continued to the end of 1999, with a total of only 2828 confirmed cases. INTERPRETATION: PAHO's measles eradication strategy has been effective in interrupting transmission and maintaining the absence of measles virus circulation in most parts of the Americas. The PAHO experience provides strong evidence that with full implementation of an appropriate vaccination strategy, measles transmission can be effectively interrupted.

Jamaica's measles elimination experience.

OBJECTIVES: This article describes the effort to eliminate measles from Jamaica and its impact on measles incidence. METHODS: In addition to routine measles vaccination, the Jamaican Ministry of Health implemented a strategy of a 1-time-only catch-up vaccination campaign, conducted in 1991, and periodic follow-up campaigns, the first of which occurred in 1995. RESULTS: Since 1991, despite careful surveillance, no serologically confirmed indigenous cases of measles have occurred in Jamaica. CONCLUSIONS: Measles virus circulation has been interrupted in Jamaica. The Jamaican experience provides further evidence that global measles eradication is achievable.

Measles in adults in Canada and the United States: implications for measles elimination and eradication.

BACKGROUND: Despite the implementation of mass school catch-up campaigns for measles in Canada, an outbreak of measles occurred in early 1997 mostly affecting the adult population. The higher incidence in Canada in adults led us to compare immunization policies and the evolution of measles among adults in Canada and the US. METHODS: Based on information gathered from both national immunization programmes and surveillance systems. RESULTS: Although the proportion of cases occurring in adults has increased tremendously in both countries in the past decade, there was no increase in measles incidence in these populations. The most likely factors to explain the higher rate of measles occurring in adults in Canada are the younger age at administration of first dose in Canada, the delay in implementation of a second dose policy in Canada compared with the US combined with the lack of prematriculation immunization requirements in Canadian colleges and universities, and the higher rate of overseas travel to and from Canada. The situation in Canada may also have been exacerbated by incomplete efforts to control measles for many years without attempting to eliminate the disease. CONCLUSIONS: In order to prevent measles in adults, high-risk groups must be identified and catch-up for selected groups considered. Vaccination of international travellers to endemic areas should be recommended until global elimination has been achieved. Appropriate measles control strategies in younger populations seem to be effective in preventing measles in adults. The experience in Canada and the US suggests that measles transmission in adults is unlikely to be a major impediment to regional elimination or global eradication.

Rational use of rubella vaccine for prevention of congenital rubella syndrome in the Americas.

Rubella is a viral disease with minor morbidity and few complication unless it is contracted by a pregnant woman. Rubella infection during the first trimester of pregnancy often leads to fetal death or severe congenital defects (congenital rubella syndrome, CRS). Rubella remains endemic in many countries of Latin America and the Caribbean. It has been estimated that 20,000 or more infants are perhaps born with CRS each year in Latin American and Caribbean countries. While the inclusion of rubella vaccination into routine childhood immunization will decrease rubella virus circulation among young children, it will not have immediate impact on the transmission of rubella among adults or the occurrence of CRS. A one-time mass campaign targeting both males and females 5 to 39 years of age with measles-mumps-rubella or measles-rubella vaccine followed by the use of measles-mumps-rubella vaccine in routine early childhood vaccination will prevent and control both rubella and CRS promptly. In April 1988, the Ministers of Health of the English-speaking Caribbean targeted rubella for elimination by the end of the year 2000 using the vaccination strategy outlined above. The rubella elimination experience of these countries will provide useful information for the eventual elimination of rubella virus from the Americas.

[Eradication of measles in Cuba]. / La eliminación del sarampión en Cuba.

The vaccine against measles came into use in Cuba in 1971. During the seventies, a new early strategy for measles control was established, and it was followed by further efforts in the early eighties. Despite improvements to the control program, disease outbreaks continued to occur. In 1986, after examining the experience acquired through the control initiatives that were already in place, a new measles vaccination strategy was adopted. In time, the new vaccination strategy against measles came to have three main components: first, a single vaccination "catching-up" campaign targeting children 1 to 14 years of age. Second, efforts were made to achieve and maintain high vaccine coverage through mandatory vaccination services for 12-month-old children ("maintenance vaccination"). Finally, periodic "follow-up" campaigns were carried out for children 2 to 6 years of age. Steps were taken, for the purpose of monitoring the progress made so far toward eliminating measles, to strengthen disease surveillance systems, including the screening of suspected cases. The "catching-up" and "follow-up" campaigns both achieved greater than 98% coverage within targeted age groups. The routine vaccination program has also maintained high coverage. The high population immunity against measles that has been attained through these vaccination strategies has resulted in a rapid decrease in the incidence of the disease. From 1989 to 1992, less than 20 laboratory-confirmed cases were reported annually. In Cuba, the last case confirmed through serologic screening was reported in July 1993. Cuba's strategy for measles elimination has interrupted disease transmission and kept the causal virus from circulating on the island. Cuba's experience with measles elimination suggests that if an appropriate vaccination strategy is applied, measles can be globally eradicated.

Measles eradication: experience in the Americas.

In 1994, the Ministers of Health from the Region of the Americas targeted measles for eradication from the Western Hemisphere by the year 2000. To achieve this goal, the Pan American Health Organization (PAHO) developed an enhanced measles eradication strategy. First, a one-time-only "catch-up" measles vaccination campaign is conducted among children aged 9 months to 14 years. Efforts are then made to vaccinate through routine health services ("keep-up") at least 95% of each newborn cohort at 12 months of age. Finally, to assure high population immunity among preschool-aged children, indiscriminate "follow-up" measles vaccination campaigns are conducted approximately every 4 years. These vaccination activities are accompanied by improvements in measles surveillance, including the laboratory testing of suspected measles cases. The implementation of the PAHO strategy has resulted in a marked reduction in measles incidence in all countries of the Americas. Indeed, in 1996 the all-time regional record low of 2109 measles cases was reported. There was a relative resurgence of measles in 1997 with over 20,000 cases, due to a large measles outbreak among infants, preschool-aged children and young adults in São Paulo, Brazil. Contributing factors for this outbreak included: low routine infant vaccination coverage, failure to conduct a "follow-up" campaign, presence of susceptible young adults, and the importation of measles virus, apparently from Europe. PAHO's strategy has been effective in interrupting measles virus circulation. This experience demonstrates that global measles eradication is an achievable goal using currently available measles vaccines.

Epidemic cholera in Burundi: patterns of transmission in the Great Rift Valley Lake region.

BACKGROUND: After a 14-year hiatus, epidemic cholera swept through Burundi between January and May, 1992. The pattern of transmission was similar to that in 1978, when the seventh pandemic first reached this region. Communities affected were limited to those near Lake Tanganyika and the Rusizi River. The river connects Lake Tanganyika with Lake Kivu to the north in Zaire and Rwanda. METHODS: To identify sources of infection and risk factors for illness, an epidemiological study was carried out in Rumonge, a lake-shore town where 318 people were admitted to hospital with cholera between April 9 and May 31, 1992. The investigation included a case-control study of 56 case-patients and 112 matched controls. FINDINGS: Attack rates according to street increased with the street's proximity to Lake Tanganyika (chi 2 test for linear trend, p < 0.01) which suggests that exposure to the lake was a risk factor for illness. Comparison of the 56 case-patients with matched controls showed that bathing in the lake (odds ratio 1.6, attributable risk percentage 37%) and drinking its water (2.78, 14%) were independently and significantly (p < 0.05) linked with illness. No food-borne risk factors were identified. Vibrio cholera 01 was isolated from Lake Tanganyika during, but not after, the outbreak in Rumonge. Isolates from the lake and from patients with acute watery diarrhoea had the same serotype, biotype, and antimicrobial susceptibility profiles. The number of cases rapidly declined when access to the lake was blocked. INTERPRETATION: This study identifies bathing in contaminated surface water as a major risk factor for cholera in sub-Saharan Africa, and suggests that improving the quality of drinking water alone will have only limited impact on the transmission of the disease in the Great Rift Valley Lake region. The similarity in the patterns of transmission during the 1978 and 1992 epidemics suggests that extensive use of the Great Lakes and connecting rivers for transportation and domestic purposes may be the reason for the explosive cholera outbreaks that occur sporadically in this region.

Eradication of wild poliovirus from the Americas: acute flaccid paralysis surveillance, 1988-1995.

In May 1985, the Pan American Health Organization proposed the goal of interruption of wild poliovirus transmission in the Western Hemisphere. An important component of the polio eradication strategy was conducting surveillance for cases of acute flaccid paralysis. Reported cases were thoroughly investigated, including the collection of stool samples for testing for the presence of wild poliovirus. The last patient with poliomyelitis due to wild poliovirus in the Americas had onset of paralysis on 23 August 1991 in Peru. Since then, >9000 cases of acute flaccid paralysis have been reported and thoroughly investigated; none has been confirmed as paralytic poliomyelitis due to wild poliovirus. On 29 September 1994, the International Commission for the Certification of Poliomyelitis Eradication declared the Americas to be polio-free.

The supplement to HIV-AIDS Surveillance project: an approach for monitoring HIV risk behaviors.

A variety of surveillance methods are used to characterize the epidemic of HIV infection and AIDS. Such surveillance includes AIDS case reporting, reporting of diagnosed HIV infections, and HIV seroprevalence surveys among targeted sentinel populations. The need for additional surveillance systems to monitor HIV-related risk behaviors has been increasingly evident. One approach to behavioral surveillance, the CDC's Supplement to HIV-AIDS Surveillance project, uses the infrastructure of HIV infection and AIDS case reporting to collect additional information on risk behaviors among HIV-infected persons, who by definition represent those at highest risk.

Measles elimination in the Americas. Evolving strategies.

The strategy currently used to control measles in most countries has been to immunize each successive birth cohort through the routine health services delivery system. While measles vaccine coverage has increased markedly, significant measles outbreaks have continued to recur. During the past 5 years, experience in the Americas suggests that measles transmission has been interrupted in a number of countries (Cuba, Chile, and countries in the English-speaking Caribbean and successfully controlled in all remaining countries. Since 1991 these countries have implemented one-time "catch-up" vaccination campaigns (conducted during a short period, usually 1 week to 1 month, and targeting all children 9 months through 14 years of age, regardless of previous vaccination status or measles disease history). These campaigns have been followed by improvements in routine vaccination services and in surveillance systems, so that the progress of the measles elimination efforts can be sustained and monitored. Follow-up mass vaccination campaigns for children younger than 5 years are planned to take place every 3 to 5 years.

The types of drugs used by HIV-infected injection drug users in a multistate surveillance project: implications for intervention.

OBJECTIVES: This study sought to describe the drugs used by drug injectors infected with human immunodeficiency virus (HIV) and to determine factors associated with the primary injection drug used. METHODS: A cross-section of persons 18 years of age or older reported with HIV or acquired immunodeficiency syndrome (AIDS) to local health departments in 11 US states and cities was surveyed. RESULTS: Of 4162 persons interviewed, 1147 (28%) reported ever having injected drugs. Of these 1147 injectors, 72% primarily injected a drug other than heroin. However, the types of drugs injected varied notably by place of residence. Heroin was the most commonly injected drug in Detroit (94%) and Connecticut (48%); cocaine was the most common in South Carolina (64%), Atlanta (56%), Delaware (55%), Denver (46%), and Arizona (44%); speedball was most common in Florida (46%); and amphetamines were most common in Washington (56%). Other determinants of the type of drug primarily injected were often similar by region of residence, except for heroin use. Polysubstance abuse was common; 75% injected more than one type of drug, and 85% reported noninjected drug use. CONCLUSIONS: Preventing the further spread of HIV will require more drug abuse treatment programs that go beyond methadone, address polysubstance abuse, and adapt to local correlates of the primary drug used.

Risk factors for HIV infection among abandoned Romanian children.

OBJECTIVE: To determine risk factors for HIV infection among abandoned Romanian infants and children living in a public institution. METHODS: A cross-sectional study was conducted in June 1990 among 101 children between 0 and 4 years of age living in an orphanage. Orphanage and hospital records were reviewed and a blood specimen for hepatitis B and HIV serologic testing obtained from each child. A case-control study was conducted using data from the cross-sectional study. Cases were HIV-positive children; one HIV-negative control, matched by age, was selected for each case. RESULTS: Overall, 20 (20%) children were HIV-positive, 88 (87%) tested positive for antibody to hepatitis B core antigen, and 32 (32%) were hepatitis B surface antigen-positive. In the case-control study, HIV-positive children had received more therapeutic injections [mean, 280; median, 231] than age-matched HIV-negative children [mean; 142, median, 155; P = 0.02]. Cases were more likely than controls to have received over 200 lifetime injections (odds ratio, 5.7; 95% confidence interval, 1.2-32.7). Blood transfusions and mother-to-child transmission were excluded as routes of HIV transmission. By reviewing sterilization records and interviewing local health-care workers, we determined that needles and syringes were often re-used without proper disinfection in the orphanage. CONCLUSIONS: These data provide strong epidemiologic evidence that indiscriminate injections with contaminated needles and syringes were responsible for HIV transmission in this population.

Hepatitis B virus infection among pregnant women in northeastern Romania.

We conducted a serological survey of pregnant women attending prenatal clinics in northeastern Romania to determine the prevalence of hepatitis B virus (HBV) infection in this population. Overall, 162 (28%) of 573 women had evidence of past or current HBV infection, and 48 (8.4%) were carriers. The prevalence of past or current infection rose with age, but did not differ by educational level, occupation, or rural versus urban residence. Integration of hepatitis B vaccine into routine childhood immunization schedules, with the first dose given at birth, may have a substantial impact on HBV infection in Romania by preventing both perinatal and early childhood transmission.

PIP: Blood-borne pathogens like hepatitis B virus (HBV) have been a major cause of human sickness and significant economic drain worldwide. Current vaccination programs are based on levels of infection in the population. Romanian orphanages were found to have children with high levels of HBV. This paper reports the findings of a serological survey for HBV in pregnant Romanian women. Blood was taken from 573 women surveyed. Each blood sample was tested for antibodies to the HBV core antigen by radioimmunoassay. Data were statistically assessed using the Z-test, the Chi-square, and the Chi-square for trend. 162/573 women (28%) had a current or past HBV infection. 48/573 women (8.4%) were considered HBV carriers, as they tested positive for hepatitis B surface antigen (HBsAg). In Romania, HBV infections are common in women giving birth. It is for this reason that a large-scale vaccination program should be a major public health priority. HBV vaccination could be incorporated into the existing routine childhood immunization schedules.

The geographic distribution of measles in the United States, 1980 through 1989.

OBJECTIVE: To describe the geographic distribution of measles cases in the United States by county for the 10-year period from 1980 through 1989. DESIGN: Ecological analysis of national measles surveillance data. METHODS: Measles cases reported to the Morbidity and Mortality Weekly Report from 1980 through 1989 were analyzed. Data from the 1980 and 1990 US censuses were used to produce demographic profiles for each of the 3137 countries. Outcome variables examined included mean annual incidence and number of years reporting measles, with use of Spearman's rank correlation coefficients to examine the association between the demographic and the two outcome variables. RESULTS: A total of 56,775 measles cases were reported during the decade. Of the nation's 3137 counties, 1690 (53.9%) did not report any cases; only 17 (0.5%) reported measles in all 10 years. Counties reporting measles more frequently during the decade had higher median populations, population densities, and percentage of black and Hispanic populations than those counties reporting less frequently. Population size, population density, and percentage of Hispanic population were associated with number of years reporting measles and mean annual measles incidence rate. Measles cases in counties reporting measles every year predominantly occurred in unvaccinated preschoolers; cases in counties reporting less frequently predominantly occurred in vaccinated school-aged children. CONCLUSIONS: This analysis illustrates the focal nature of measles in the United States during the past decade. Most counties have not reported a single case of measles during the entire decade, and only 17 counties reported measles every year. Targeted strategies are needed to improve age-appropriate immunization levels among preschool-aged children living in large inner-city areas.

Acquired immunodeficiency syndrome in Romania.

After the initial description of acquired immunodeficiency syndrome (AIDS) in Romania in late 1989, national AIDS case surveillance was established with a modified version of the World Health Organisation (WHO) clinical case definition. This modified case definition requires that AIDS cases have both clinical and serological evidence of human immunodeficiency virus (HIV) infection. Before December, 1989, Romania had reported 13 AIDS cases to WHO. By Dec 31, 1990, 1168 AIDS cases were reported to Romania's Ministry of Health, of which 1094 (93.7%) occurred in children less than 13 years of age at diagnosis. Of these, 1086 (99.3%) were in infants and children less than 4 years of age, and 683 (62.4%) in abandoned children living in public institutions at the time of diagnosis. By Dec 31, 1990, 493 (45.1%) mothers of children with AIDS had been located and tested, and 37 (7.5%) were positive for HIV; 423 (38.7%) cases were in children who had received transfusions of unscreened blood, and 6 (0.5%) were in children with clotting disorders. HIV transmission through the improper use of needles and syringes is strongly suspected in most of the remaining 628 (57.4%) children with AIDS, most of whom had received multiple therapeutic injections. This outbreak demonstrates the serious potential for HIV transmission in medical facilities that intensively and improperly use parenteral therapy and have poor sterilisation technique.

PIP: As a recently established AIDS surveillance system has revealed, the overwhelming majority of AIDS cases in Romania have occurred among children. Before December 1989, Romania had reported only 13 cases of AIDS to the World Health Organization (WHO). But following the change in government at the end of 1989, the newly organized Ministry of Health requested emergency assistance from WHO is setting up a surveillance system, having heard reports of large numbers of children with HIV infection. Prior to the 1989 revolution, many parents would abandon their newly born infants, and many of these children would became wars of the state. The infants were cared for in either orphanages or chronic-care hospitals for malnourished children. By December 1990, the surveillance had uncovered 1168 AIDS cases, 1094 (93.7%) of whom were children under 13 years of age. This figure surpasses the total number of AIDS cases among children in all other European countries combined since 1981. Among Romania's infected children, 1086 (99.3%) were infants under 4 years of age, and 683 (62.4%) were wards of the state. As of December 1990, researchers had located and tested 493 (45.1%) of the mothers of children with AIDS. 37 (7.5%) of them tested HIV- positive. Researchers also found that 423 (38.7%) of the children had become infected through transfusion of unscreened blood, and that 6 (0/5%) cases were among children with clotting disorders. The surveillance experts suspect that the remaining 628 (57.4%) of the cases are among children who received multiple therapeutic injections, indicating the serious potential for HIV transmission in medical facilities that improperly use parenteral therapy and have poor sterilization techniques.

Mumps outbreak in a highly vaccinated population.

From October 1988 to April 1989, a large mumps outbreak occurred in Douglas County, Kansas. Of the 269 cases, 208 (77.3%) occurred among primary and secondary school students, of whom 203 (97.6%) had documentation of mumps vaccination. Attack rates were highest for students attending junior high school (8.0%), followed by high school (2.0%) and elementary school (0.7%). A retrospective cohort study conducted at one junior high school with an attack rate of 12.9% did not find age at vaccination or type of vaccine received (single or combined antigen) to be risk factors for vaccine failure. Students vaccinated more than 4 years before the outbreak appeared to have a higher attack rate than those vaccinated more recently (relative risk (RR) = 4.3; 95% confidence interval (CI) = 0.6, 30.0); however, this association did not exist when risk was evaluated based on number of vaccine doses received. Students who had documentation of receiving only one dose of vaccine were at greater risk than those who had received two doses (RR = 5.2; 95% CI = 1.0, 206.2). Overall, vaccine effectiveness among Douglas County junior high school students was estimated to be 83% (95% CI = 57%, 94%). These data suggest that mumps vaccine failure and the failure to vaccinate have contributed to the relative resurgence of mumps observed in the United States since 1986. The recent change in immunization policy to recommend a two-dose schedule of measles-mumps-rubella vaccine should help reduce the occurrence of mumps outbreaks in highly vaccinated populations.

A measles outbreak at a college with a prematriculation immunization requirement.

BACKGROUND: In early 1988 an outbreak of 84 measles cases occurred at a college in Colorado in which over 98 percent of students had documentation of adequate measles immunity (physician diagnosed measles, receipt of live measles vaccine on or after the first birthday, or serologic evidence of immunity) due to an immunization requirement in effect since 1986. METHODS: To examine potential risk factors for measles vaccine failure, we conducted a retrospective cohort study among students living in campus dormitories using student health service vaccination records. RESULTS: Overall, 70 (83 percent) cases had been vaccinated at greater than or equal to 12 months of age. Students living in campus dormitories were at increased risk for measles compared to students living off-campus (RR = 3.0, 95% CI = 2.0, 4.7). Students vaccinated at 12-14 months of age were at increased risk compared to those vaccinated at greater than or equal to 15 months (RR = 3.1, 95% CI = 1.7, 5.7). Time since vaccination was not a risk factor for vaccine failure. Measles vaccine effectiveness was calculated to be 94% (95% CI = 86, 98) for vaccination at greater than or equal to 15 months. CONCLUSIONS: As in secondary schools, measles outbreaks can occur among highly vaccinated college populations. Implementation of recent recommendations to require two doses of measles vaccine for college entrants should help reduce measles outbreaks in college populations.