Impact of mass measles campaigns among children less than 5 years old in Uganda

In 1999-2001, a national measles control strategy was implemented in Uganda, including routine immunization and mass vaccination campaigns for children aged 6 months to 5 years. This study assesses the impact of the campaigns on measles morbidity and mortality. Measles cases reported from 1992 through 2001 were obtained from the Health Management Information System, and measles admissions and deaths were assessed in six sentinel hospitals. Measles incidence declined by 39%, measles admissions by 60%, and measles deaths by 63% in the year following the campaigns, with impact lasting 15 to 22 months. Overall, 64% of measles cases were among children <5 years of age, and 93% were among children 相似文献   

Evaluation of urban measles mass campaigns for children aged 9-59 months in Mali

There are an estimated 234,000 cases of measles and 13,851 measles-related deaths per year in Mali. In 1998 and 1999, 548,309 children aged 9-59 months were vaccinated against measles during mass campaigns in urban centers across Mali. After the first campaign, measles incidence decreased by 95% in districts encompassing vaccinated urban centers and by 41% in nonvaccinated districts. There was no shift in the proportion of cases by age group in vaccinated centers. Measles in vaccinated districts after the campaign was likely related to persistent transmission in age groups not targeted for vaccination and among children living in nonvaccinated districts. The second campaign (1999) did not change the incidence of measles in vaccinated compared with nonvaccinated centers. Urban mass measles vaccination probably did not affect overall measles transmission in Mali. Mass vaccination of all children in Mali, targeting a larger age group, will be necessary to reach measles control objectives.     

Measles vaccination coverage during poliomyelitis national immunization days in Burkina Faso, 1999

In 1999, Burkina Faso added measles vaccine during the second round of its poliomyelitis national immunization days (NIDs). A cluster survey was conducted in each of the country's 53 health districts to assess vaccination coverage achieved by the campaign. Forty-four percent of children aged 9-59 months had a documented prior measles vaccination, and 88% were vaccinated during NIDs. Eighty-five percent of children not previously vaccinated received measles vaccine during the campaign. Although routine vaccination coverage varied substantially among children from various socioeconomic groups, the campaign appeared to almost equally reach all groups of children surveyed. Poliovirus vaccine coverage was 90% when measles vaccine was added to the campaign, compared with 88% during the first round. In Burkina Faso, the addition of measles vaccine to poliomyelitis NIDs achieved greater equity in measles vaccination coverage according to a number of socioeconomic factors without compromising the coverage of poliovirus vaccination.     

Progress toward interruption of endemic measles transmission in Tunisia

Measles was the second leading cause of infant mortality in Tunisia prior to introduction of measles vaccination in 1979. The number of reported measles cases has decreased from 3007 in 1981 to 47 cases in 2000 due in part to the high coverage rates achieved after 1992. During 1998, a measles catch-up campaign vaccinated 1,846,657 children (95%) aged 6-16 years, and a follow-up campaign for children aged 9 months to 5 years in 2001 reached 547,766 (94%). During 1999-2001, 1717 cases of rash and fever illness were tested for measles; only 3 (0.2%) were positive for measles. From February to July 2002, an outbreak of measles involving 87 cases occurred in Tunisia in a health care setting and 56 (64%) patients were aged 15-30 years. The low number of laboratory-confirmed measles cases during 1999-2001 suggests endemic measles transmission may have been interrupted.     

Interruption of indigenous measles transmission in Bolivia since October 2000

Measles incidence in Bolivia declined after the introduction of campaign strategies in the 1980s. From 1990 to 1993, the peak incidence of measles (59 cases/100,000 population) was in 1992. In 1994, after the goal of interruption of measles transmission was adopted, a national vaccination campaign targeting children <15 years old was conducted and achieved 96% coverage. During 1995-1997, cases declined, although routine coverage was <90% in most years. During 1998-2000, a nationwide epidemic occurred among 2567 case-patients, most of whom were unvaccinated. A national vaccination campaign, with strong supervision, was conducted during November and December 1999 and targeted areas with low coverage. Only 122 cases were confirmed in 2000, with the last confirmed case occurring in October. Crucial to the control of the outbreak were sufficient resources and political support, intensive local planning, door-to-door vaccination with strict supervision, and rapid house-to-house coverage monitoring that improved accountability at the local level and timely and thorough outbreak investigations.     

Failure of targeted urban supplemental measles vaccination campaigns (1997-1999) to prevent measles epidemics in Mozambique (1998-2001)

This study assessed the effect of urban supplemental measles vaccination campaigns (1997-1999) in Mozambique that targeted children aged 9-59 months. Reported measles cases were analyzed to the end of 2001 to determine campaign impact. Hospital inpatient data were collected in the national capital and in three provincial capitals where epidemics occurred the year after the campaigns. Measles epidemics followed campaigns in the capital city, in 4 of 9 provincial capitals, and in 39 of 126 districts. Reasons for limited campaign impact included a low proportion of urban dwellers, the geographic location of some provincial capitals, the limited target age group, and low routine and campaign coverage. Routine immunization and disease surveillance should be strengthened and campaigns must achieve >90% coverage and target wider age groups and geographic areas in order to reach a high proportion of persons susceptible to measles.     

Measles in Mexico, 1941-2001: interruption of endemic transmission and lessons learned

In Mexico, measles occurred in a cyclical endemic-epidemic pattern until the early 1970s. Beginning in 1973, routine vaccination augmented by mass vaccination campaigns led to a decrease in the incidence of measles until the 1989-1990 regional pandemic, when the measles attack rate rose to 80 cases per 100000, resulting in 5899 deaths. Since the pandemic, measles elimination efforts in Mexico have resulted in increasing coverage to >95% among children aged 1-6 years with 2 doses of either measles or measles-mumps-rubella vaccine since 1996 and in coverage of 97.6% among children aged 6-10 since 1999. Surveillance data suggest that the transmission of indigenous measles virus was interrupted in 1997. After almost 4 years without measles cases, in April 2000, measles virus was reintroduced into Mexico and 30 laboratory-confirmed cases were reported. Detection of relatively few cases in nonprogrammatic age groups affirms the high immunization coverage and the sensitivity of measles surveillance in Mexico. We conclude that the specific strategies adopted for measles elimination have enabled Mexico to eliminate the endemic transmission of measles.     

Impact of alternative approaches to accelerated measles control: experience in the African region, 1996-2002

From 1996 to 2000, several African countries accelerated measles control by providing a second opportunity for measles vaccine through supplemental campaigns. Fifteen countries completed campaigns in children aged 9 months to 14 years. Seven countries completed campaigns in children aged 9-59 months. In almost all countries that conducted campaigns in children aged 9 months to 14 years, measles deaths were reduced to near zero. In six countries, near-zero measles mortality has been maintained for 4-6 years. Supplemental immunization in children <5 years old was only partially effective (range, 0-67%) in reducing mortality. Measles cases decreased by 50% when routine vaccination coverage increased from 50% to 80%. Initial measles campaigns in children aged 9 months to 14 years, follow-up campaigns in those aged 9-59 months every 3-5 years, and increased routine coverage to 80% will be needed to reduce and maintain measles deaths in African countries at near zero.     

Approach to verify the status of measles, rubella, and congenital rubella syndrome elimination in Costa Rica

Costa Rica introduced the measles-mumps-rubella (MMR) vaccine in 1986. The Ministry of Health adopted the goal of eliminating endemic measles in 1991 by achieving and maintaining high vaccine coverage through routine delivery, mass campaigns and outreach activities, and the strengthening of expanded program on immunization (EPI) surveillance. Measles and rubella immunization strategies shifted susceptibility to older age groups, leading to the introduction of MMR2 in 1992, administered at age 7 years. In 2000, the goal of accelerated rubella control and congenital rubella syndrome prevention was established, and a nationwide vaccination campaign targeting men and women aged 15-39 was implemented to immunize the population of reproductive age. The last endemic case of measles was confirmed in 1999, and at the end of 2001 Costa Rica reported the last endemic cases of rubella and congenital rubella syndrome. Imported cases of measles and rubella were detected in 2003 and 2005, with no secondary cases detected. In 2008, Costa Rica established a National Committee of Experts, supported by technical teams, to collect the evidence required to verify the interruption of endemic transmission of the measles and rubella viruses. The evidence includes information on trends and epidemiologic analysis, molecular epidemiology, population immunity, the quality of surveillance, and the sustainability of the EPI program.     

Implementation of a mass measles campaign in central Afghanistan,December 2001 to May 2002

In Afghanistan health services have been disrupted by 23 years of conflict and 1 of 4 children die before age 5 years. Measles accounts for an estimated 35,000 deaths annually. Surveillance data show a high proportion of measles cases (38%) among those >/=5 years old. In areas with complex emergencies, measles vaccination is recommended for those aged 6 months to 12-15 years. From December 2001 to May 2002, Afghan authorities and national and international organizations targeted 1,748,829 children aged 6 months to 12 years in five provinces in central Afghanistan for measles vaccinations. Two provinces reported coverage of >90% and two >80%. Coverage in Kabul city was 62%. A subsequent cluster survey in the city found 91% coverage (95% confidence interval [CI], 0.85-0.91) among children 6-59 months and 88% (95% CI, 0.87-0.95) among those 5-12 years old. Thus, this campaign achieved acceptable coverage despite considerable obstacles.     

Use of administrative data to estimate mass vaccination campaign coverage,Burkina Faso, 1999

Administrative coverage data are commonly used to assess coverage of mass vaccination campaigns. These estimates are obtained by dividing the number of doses administered by the number of children of eligible age, usually at the health district level. This study used data from a cluster survey conducted in each of the 53 Burkina Faso health districts immediately after 1999 the National Immunization Days to assess whether administrative estimates correlated with those obtained through survey and whether the former identified districts that achieved suboptimal coverage as measured by cluster survey. During the first round of the campaign there was no significant correlation between data obtained by either method. The correlation was only marginally better during the second round. Although useful to help plan the logistics of a campaign, administrative coverage data should be used with other evaluation techniques in order to determine the number of eligible children vaccinated during a mass campaign.     

Measles epidemiology and elimination strategies in Turkey

In Turkey, 15,000-30,000 measles cases have been reported annually since the 1990s. Epidemics occur every 3-4 years, and >/=90% of cases are <15 years old. The high incidence is due to inadequate vaccination coverage (nationally 84% in 2001) and immunity provided by the first dose of vaccine administered at age 9 months. The second dose, which has been recommended for first grade students since 1998, has been insufficient to provide the herd immunity necessary to control measles. The Ministry of Health launched a comprehensive program for 2002-2010 targeting measles elimination. This plan calls for a national vaccination campaign among all children aged 9 months to 14 years and routine two-dose vaccination coverage will be increased to >/=95% or follow-up campaigns will be conducted in areas not achieving high coverage levels. Also, all military recruits in 2002-2009 will be vaccinated and case-based, laboratory supported surveillance will be initiated.     

Progress toward measles elimination in Romania after a mass vaccination campaign and implementation of enhanced measles surveillance

In response to an outbreak of >33,000 measles cases in 1996-1998 and to prevent an outbreak predicted for 2002, Romania conducted a nationwide measles-rubella vaccination campaign in October 1998. Some 2.1 million children aged 7-18 years were vaccinated. Data from national surveillance and seroprevalence studies conducted in three districts were used to assess the campaign and status of measles control. Surveillance data showed a dramatic drop in measles despite enhanced surveillance starting in October 1999. From October 1999 to December 2001, 400 suspected measles cases were reported, down from about 5000 cases annually in non-outbreak years. Only 29 (8%) of 386 cases with specimens were laboratory confirmed; 14 were clinically confirmed. Seroprevalence estimates showed high measles antibody levels before (92.9%) and after (94.4%) the campaign. The low number of laboratory-confirmed cases and high population immunity suggest that interruption of indigenous measles virus transmission is a real possibility for Romania.     

Progress toward measles and rubella elimination in Egypt

Measles and rubella were common infectious diseases in Egypt during the prevaccine era. Monovalent measles vaccine was introduced in 1977, and measles vaccination coverage increased from <50% to >90% from 1980 to 1999; however, measles outbreaks continued to occur at 2- to 4-year intervals during this period. After the introduction of a second routine dose of measles vaccine as a combined measles-mumps-rubella (MMR) vaccine in 1999 and the implementation of measles immunization campaigns targeting 6- to 16-year-old children during 2000-2003, reported measles cases dramatically decreased by 2003. In 2002, Egypt established a goal to eliminate measles and rubella and to prevent congenital rubella syndrome (CRS) by 2010. Large-scale rubella and measles outbreaks in 2005-2007, however, led to a revision of the plan of action to achieve the 2010 goals. A nation-wide measles-rubella immunization campaign, targeting children, adolescents, and young adults 2-20 years old, was conducted in 2 phases during 2008-2009 and achieved coverage >95%. With the decrease to record low levels of cases of measles and rubella in 2009 and 2010, Egypt should achieve measles and rubella elimination in the near future, but high coverage(>95%) with 2 doses of measles-rubella vaccine needs to be maintained, measles-rubella surveillance strengthened, and CRS surveillance developed.     

The challenge of achieving measles elimination in the eastern Mediterranean region by 2010

In 1997, the Eastern Mediterranean Region (EMR) of the World Health Organization adopted a resolution to eliminate measles by 2010. Of the 23 EMR member countries, 18 are polio-free and are building on this success to eliminate measles. The 5 countries where polio remains endemic are prioritizing polio eradication and working to improve measles control. Measles incidence has been reduced from 193/100,000 in 1981 to 6.8/100,000 in 2001. Supplemental vaccination campaigns for measles have been conducted since 1994 in 14 of the 18 polio-free countries. More than 50 million children have been immunized in these supplemental activities. However, in Afghanistan, Sudan, Somalia, Djibouti, and Pakistan, where 34% of the EMR population live, routine vaccination coverage for measles remains below 60% and measles deaths are estimated at 81,000 annually among children <5 years old. Significant resources must be allocated to these last 5 countries to achieve regional measles elimination by 2010.     

Progress toward measles eradication in the region of the Americas

Since 1994, when the goal of interrupting indigenous measles transmission was adopted, important progress has been made toward the control of measles in the Americas. Thirty-nine (95%) of 41 countries reporting to the Pan American Health Organization (PAHO) conducted catch-up vaccination campaigns during 1989-1995 and follow-up measles campaigns every 4 years. Routine (keep-up) vaccination coverage in the Region increased from 80% in 1994 to 94% in 2000. Measles vaccination coverage ranged between 75% and 99% in 2000 and between 53% and 99% in 2001. As a result, in 2001, the total number of confirmed measles cases reached a record low of 537, 99% lower than the number reported in 1990. In 2002, only Venezuela and Colombia had known indigenous transmission. As of January 2003, no known indigenous measles transmission had occurred in the Region since November 2002. This is due to high political commitment and implementation of PAHO's recommendations, including strengthened supervision and monitoring to improve accountability at the local level.     

Successful control and impending elimination of measles in the Islamic Republic of Iran

Measles is still one of the most common infectious killers of children in the world, especially in developing countries. In Iran, during the prevaccine era, 150,000-500,000 cases of measles were reported annually, with a death rate of 10%-15%. After the establishment of Expanded Program on Immunization program in 1984, vaccination rates for the first and second doses of measles vaccine increased to >90% by the mid-1990s, and the number of measles cases decreased to 2652 in 1996. In response to increased numbers of cases in older age groups during 1996-2002, a nationwide measles-rubella vaccination campaign was conducted in 2003, and 33,100,000 persons (99%) aged 5-25 years were vaccinated. During 2004-2009, 221 laboratory-confirmed measles cases (<1 case per million population) were detected, primarily in rural areas and among migrant groups who traveled to or came from high-incidence countries. High routine immunization coverage, low disease incidence, and surveillance system data suggest that interruption of endemic virus transmission might have already been achieved in Iran, but challenges remain and continued efforts are needed to sustain this accomplishment.     

Measles eradication in the Americas: progress to date

The region of the Americas has shown extraordinary progress in its fight to interrupt measles transmission. The Pan American Health Organization's recommended strategy includes the following: a 1-time nationwide campaign targeting 1- to 14-year-old children; routine vaccination among 1-year-olds; and nationwide campaigns conducted every 4 years, targeting all 1- to 4-year-olds. Rapid house-to-house monitoring of vaccination and measles surveillance are other essential components of the strategy. During 2001, only 541 cases were confirmed in the region. In 2002, only Venezuela and Colombia had indigenous transmission. After important vaccination efforts in both countries, the last reported case occurred on 20 September 2002, in Venezuela. Since then, no confirmation exists of indigenous measles circulation anywhere else in the region. Nonetheless, important challenges remain, including insufficient coverage during routine and campaign vaccination and inadequate investigation of some cases.     

Impact of nationwide measles vaccination campaign among children aged 9 months to 14 years,Zimbabwe, 1998-2001

Zimbabwe (population 11,365,000) introduced nationwide one-dose measles vaccination in 1981. This strategy reached 70%-80% of infants <1 year of age over the next two decades; in 1998, a nationwide supplemental immunization activity (SIA) targeting all children aged 9 months to 14 years achieved 93% coverage. Surveillance data were examined to determine the impact of these strategies. During 1985-1997, there were 8529-49,812 measles cases annually. After the SIA, laboratory confirmation of the first 5 outbreak cases and all sporadic cases was required. In 1999 and 2000, 1343 (88%) of 1534 suspected cases had adequate specimens submitted and 28 (2%) were measles IgM positive. In 2001, of 529 suspected cases, 513 (97%) had adequate specimens and only 7 (1%) were measles IgM positive. These data suggest that indigenous measles transmission in Zimbabwe has been interrupted and that high prevalence of human immunodeficiency virus seropositivity does not hinder vaccination-induced measles control. High vaccination coverage obtained through the routine health care system supplemented by periodic follow-up SIAs will be required to maintain low transmission levels.     

Measles-rubella mass immunization campaign in Albania,November 2000

In 2000, Albania resolved to eliminate measles by 2007 by use of a four-step program: by conducting a "catch-up" vaccination campaign for all children aged 1-14 years, achieving and sustaining high coverage (>/=95%) among children aged 1 year with the first dose of a measles-containing vaccine, by introducing a routine second dose of measles-containing vaccine for children at age 5 years, and by improving measles surveillance. This catch-up campaign took place in November 2000: 867,000 doses of measles-rubella vaccine were administered for an estimated coverage of 99%. In all, 231 campaign-related adverse events were reported: syncope, 206; allergic reactions, 10; fever, 8; encephalitis/encephalopathy, 2; and aseptic meningitis, seizures, Guillain-Barré syndrome, anaphylaxis, and arthralgia, 1 each. All resolved without sequelae. This report describes the status of measles and rubella/congenital rubella syndrome control in Albania before 2000 and reports on implementation of the catch-up campaign.