Interruption of measles transmission in Gipuzkoa (Basque Country), Spain

Measles vaccine was introduced in Gipuzkoa (Basque country, Spain) in 1978 and was replaced by the measles, mumps, and rubella (MMR) vaccine for children aged 12-15 months in 1981. A second dose of the MMR vaccine was introduced in 1992. Both doses of the MMR vaccine were well accepted by the population and high coverage was achieved (95% and 91% for the first and second doses respectively for the period 1993-2002). Measles virus circulation was interrupted in the second half of the 1990s: no cases of indigenous measles were notified between 1998 and 2003, and only imported cases have been confirmed during this period. These data indicate that the measles vaccination programme implemented has been effective. Nevertheless, to avoid measles outbreaks following viral introduction, high MMR vaccine coverage levels for the two doses have to be maintained (>95%).     

Toward measles elimination in Bahrain--a Middle East country experience

Measles was a leading cause of infant and child morbidity and mortality in Bahrain before the introduction of measles vaccine in 1974. With the establishment of the Expanded Program on Immunization (EPI) in 1981 and the introduction of a second dose of measles vaccine in 1985, coverage for first and second doses of measles vaccine increased to 94% by 1997 and has been sustained >97% since 2001. Measles, mumps, and rubella (MMR) immunization campaigns targeting 12-year-old students were conducted annually during 1998-2006 and achieved coverage of >95%. As a result, the incidence of measles in Bahrain has declined markedly over the past 4 decades, to 2.7 cases per million persons in 2009. Recent confirmed measles cases have occurred sporadically, in undervaccinated children or in infants too young or adults too old to receive measles vaccine. Bahrain has made significant progress toward measles elimination by sustaining high immunization coverage and strengthening case-based measles surveillance activities. Further success will depend on improved identification and immunization of undervaccinated expatriate workers and their families.     

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.     

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.     

Epidemiology of rubella in Finland

Before rubella vaccination programmes began, rubella infection was prevalent in Finnish children. The disease occurred as epidemics at intervals of a few years. Rubella infection was most often contracted between the ages of 2 and 12 years. Vaccinations specifically aimed at eradicating rubella were begun with monocomponent vaccine in the mid-1970s, and the measles, mumps and rubella (MMR) vaccination programme with two injections got underway in 1982. A clear reduction in rubella cases was evident a few years after the launch of the MMR programme. Owing to a sufficiently high vaccination coverage (>95% since 1987), circulation of the indigenous rubella virus in the Finnish population ceased in the late 1990s. Some rubella cases have been imported to Finland since elimination, but they have not caused any secondary cases. This shows unambiguously that protection against rubella continues to be effective, although our cohort studies imply that the vaccine induced antibody levels do decrease with time. The MMR programme has also eliminated congenital rubella syndrome (CRS) from the country. The last CRS case was recorded in 1986. As a result of the high coverage two dose MMR vaccination programme, rubella was successfully eliminated from Finland. How long the acquired protection will last remains to be seen.     

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.     

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.     

Vaccination levels associated with lack of measles transmission among preschool-aged populations in the United States, 1989-1991

Knowledge of the minimum level of vaccination capable of preventing measles transmission in an age group is helpful for establishing program targets for measles elimination. In 1990, during the measles resurgence in the United States, one-half of cases occurred in children aged <5 years. Although estimated population immunity among persons >or=6 years of age was 93%, immunity was lower and varied widely among preschool-aged children. To examine the association of vaccine coverage at 2 years of age and measles incidence among preschool-aged children, we analyzed ecological studies of measles incidence in Milwaukee (Wisconsin) census tracts, Dallas (Texas) ZIP code areas, and selected cities during the 1989-1991 measles resurgence. In each study area, measles incidence decreased rapidly with increasing measles vaccine coverage and became low or negligible when coverage was >or=80%. Regression analysis also suggested that measles would not be transmitted when vaccine coverage was at least 79%. A minimum vaccine coverage of approximately 80% at the second birthday in census tracts, ZIP code areas, and cities in the United States may be sufficient to prevent measles transmission among preschool-aged children if population immunity is >or=93% among persons >or=6 years of age.     

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.     

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.     

Immunization of healthy children with measles-mumps-rubella trivalent vaccine simultaneously given with varicella vaccine]

Trivalent vaccine, containing measles TD97, rubella TCRB-19 and mumps NK-M46 strains (MMR vaccine) was administered to a total of 116 healthy children of which 50 subjects were simultaneously injected with varicella vaccine in the opposite arm. The seroconversion rates for measles, mumps, rubella, and varicella in those who received both MMR and varicella vaccines (MMR + V group) were 100% (44/44), 91% (39/43), 100% (46/46) and 95% (39/41), respectively. And these rates were comparable to those in subjects receiving only MMR vaccine, namely 100% (64/64) for measles, 95% (57/62) for mumps, and 97% (58/60) for rubella. Fifty-eight children receiving MMR vaccine were seronegative to measles, mumps and rubella before vaccination, and 51 (88%) of them were found to be seropositive against all three viruses at 6 to 8 weeks after vaccination. Among the children injected with MMR and varicella vaccines, 36 subjects had no pre-antibodies to measles, mumps, rubella and varicella. Seroconversion in post-serum to all four viruses were found in 31 cases (86%). Clinical reactions observed in some vaccines were mild fever (17%) and exanthem (5%). There were no complications of lymphadenopathy, swelling in parotid regions, or meningitis. Our results indicate that simultaneous administration of MMR vaccine and varicella vaccine is a safe and effective method for immunizing children against these four infectious diseases.     

Measles in Vaccinated People: Epidemiology and Challenges in Surveillance and Diagnosis in the Post-Elimination Phase. Spain, 2014–2020

The MMR vaccination program was introduced in Spain in 1981. Consistently high vaccination coverage has led to Spain being declared free of endemic measles transmission since 2014. A few imported and import-related cases were reported during the post-elimination phase (2014 to 2020), with very low incidence: three cases per million of inhabitants a year, 70% in adults. In the post-elimination phase an increasing proportion of measles appeared in two-dose vaccinated individuals (up to 14%), posing a challenge to surveillance and laboratory investigations. Severity and clinical presentation were milder among the vaccinated. The IgM response varied and the viral load decreased, making the virus more difficult to detect. A valid set of samples (serum, urine and throat swab) is strongly recommended for accurate case classification. One third of measles in fully vaccinated people was contracted in healthcare settings, mainly in doctors and nurses, consistent with the important role of high intensity exposure in measles breakthrough cases. Surveillance protocols and laboratory algorithms should be adapted in advanced elimination settings. Reinforcing the immunity of people working in high exposure environments, such as healthcare settings, and implementing additional infection control measures, such as masking and social distancing, are becoming crucial for the global aim of measles eradication.     

Progress toward measles elimination in Germany

While the former East Germany (FEG) achieved a reduction of measles incidence to <1 case per 100,000 population before reunification in 1990, the former West Germany (FWG) experienced significant measles morbidity. In 2001, according to statutory surveillance data, the incidence of measles was still higher in FWG than in FEG (8.7 vs. 0.7 cases/100,000 population). This article describes the development of the vaccination strategies in FEG and FWG, vaccination coverage, results of seroprevalence studies, measles surveillance in Germany, the epidemiology of a recent outbreak, and the role of laboratory diagnosis for measles control in Germany. Recent establishment of comprehensive nationwide surveillance and prevention programs to attain higher vaccine coverage have led to a decrease in measles incidence. However, further improvement of age-appropriate vaccine coverage and closure of immunity gaps in school-age children are necessary to eliminate measles in Germany.     

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.     

Epidemic diphtheria in Belarus, 1992-1997

In 1990, epidemic diphtheria reemerged in Russia and spread to Belarus in 1992, when 66 cases were reported. Diphtheria cases doubled each year in 1993 and 1994 and peaked in 1995, when 322 cases were reported. Intensified routine immunization of young children and mass vaccination of older children and selected groups of adults were conducted in 1995 and were followed by mass vaccination campaigns targeting all adults in 1996. By the end of 1996, full immunization of >95% of children and coverage of>87% of adults with >/=1 dose resulted in a rapid decline in diphtheria cases. In 1998, only 36 cases of diphtheria were reported. More than 70% of the 965 cases and 26 fatalities reported during 1990-1998 occurred among persons >14 years of age. High levels of immunity among the entire population are needed for rapid control of diphtheria epidemics in the vaccine era.     

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.     

Evolution of the measles vaccination program in Costa Rica

The vaccination program instituted in Costa Rica in 1967 has had a great impact on measles. Since 1973 the downturn in its incidence and in mortality due to the disease are due solely to the continued vaccination of susceptible children throughout the country. An epidemic outbreak occurred in 1977. Since the vaccine was given primarily to children of school age, this outbreak probably was the result of an accumulation of susceptible subjects. There was little change in the mortality rates. Programs resulting in a coverage of 70% attempted to prevent a new outbreak in 1979, but failed. Because the vaccine was routinely administered to children one year of age and older, most of the cases were in the group younger than that age. At present, the incidence of measles is minimal, and no fatalities occurred in 1981. Vaccination coverage for children two years of age exceeds 90%, and Costa Rica's goal is the complete eradication of the disease.     

An outbreak of mumps in the metropolitan area of Walsall, UK.

OBJECTIVE: To describe the epidemiology of excessive mumps cases during the year 2000, within the metropolitan area of Walsall, UK; to assess the impact of the mumps outbreak on morbidity; and to inform future communicable disease control strategy. METHODS: Demographic records, school attendance, uptake of the measles-mumps-rubella (MMR) vaccine, and mumps-associated admission to hospital, were reviewed for all Walsall residents diagnosed and notified with mumps during the year 2000. RESULTS: There were 200 mumps notifications in 2000 (76.6 per 100,000), representing the highest incidence in England. Only 91 of the notified cases were salivary antibody positive for mumps IgM, and 32 were negative, although 77 were not tested. Since 1990, annual totals have never previously exceeded 20. Over 90% of patients were <20 years old, with a peak age group of 10-14 years; 88% attended schools located within Walsall. The pattern of spread suggested that the outbreak proceeded through schools from north to south in the more deprived western half of the metropolitan area. Most cases (136, 68%) had received one (99, 49.5%) or two (37, 18.5%) doses of MMR vaccine; cases > or =20 years old had never received MMR. Six cases (aged 4-14 years) were admitted to hospital, all with a successful outcome, including one male with meningitis and one female with pancreatitis. Current uptake of the MMR vaccine at 24 months has dropped to below 90% in recent years, as in most parts of the UK. CONCLUSIONS: Future mumps outbreaks in schools, and among older age groups, can be predicted, since most older children and young adults have received only one dose of MMR vaccine or no vaccination at all. Primary vaccine failure is well described in mumps, and cases during outbreaks can include recipients of two MMR vaccine doses. It was fortunate that no severe morbidity was associated with this outbreak (prior to MMR, two to four mumps deaths occurred annually in England and Wales). Measures to restore the uptake of MMR to the previous levels of above 90-95% will be necessary to reduce the risk of the mumps virus circulating within communities. Older children are susceptible, and it may be advisable to ensure second-dose MMR uptake while they are still at or when they leave school, or when they enter college, university or the military.     

Prevalence of measles susceptibility in hospital staff. Evidence to support expanding the recommendations of the Immunization Practices Advisory Committee.

BACKGROUND--In 1989 and 1990, measles reached epidemic proportions in the United States, including several areas of California. Children's Hospital Oakland (Calif), a major health care provider for children in a measles epidemic area of California, reported 131 cases between 1989 and 1991, the largest number ever reported by that institution. In February 1990, four cases of measles were reported among hospital staff. Continued risk of nosocomial infection prompted the development of a program to ensure that all hospital staff were adequately protected against measles. METHODS--All hospital employees who were unable to document proof of measles immunity were required to be serologically screened for measles antibody and to be vaccinated against measles if they were determined to be nonimmune. Serologic screening was performed in-house with a commercially available enzyme-linked immunosorbent assay measles antibody test. Dates of birth were recorded for all employees screened. Individuals with negative or repeatedly equivocal results were considered to be nonimmune and were vaccinated with trivalent measles-mumps-rubella vaccine. RESULTS--Between March and June 1990, 1694 staff were serologically tested for measles antibody. Eighty-nine (5.3%) of the employees were considered to have inadequate immunity. Forty (45%) of these susceptible individuals were born before 1957. CONCLUSIONS--We conclude that the recommendations of the Immunization Practices Advisory Committee should be expanded to include serologic screening or vaccination of hospital personnel who were born before 1957. Serologic screening of hospital staff may be a reasonable alternative to vaccination under certain circumstances.     

Post mass-immunization measles outbreak in Taoyuan County, Taiwan: dynamics of transmission, vaccine effectiveness, and herd immunity.

OBJECTIVES: Analysis of national surveillance data and a seroepidemiologic investigation were conducted to elucidate the causes and epidemiologic characteristics of a measles outbreak in Taoyuan, Taiwan, 1994. METHODS: Measles cases were identified through a national surveillance system. Reported cases and their physician or school nurses were interviewed to trace additional suspect cases and were sampled for serologic diagnosis. Measles-specific IgG and IgM were assayed. A confirmed case was defined as being positive for measles IgM test but not having received measles vaccination within the previous 3 months. RESULTS: The outbreak began in Taoyuan City in December 1993 and continued to spread in primary schools and kindergartens, but caused only sporadic cases in neighboring towns. Among 42 confirmed cases, 15 (38%) were primary school children and 16 (38%) were kindergarten children. Among 24 confirmed cases with a vaccination record, 7 had one dose of vaccination, 4 had two doses of vaccination, and 13 (54%) were unvaccinated. The overall measles susceptible proportion at a kindergarten before the outbreak was 8.1% (17/209) and the overall measles cumulative incidence among susceptibles was 0.65 (11/17). CONCLUSIONS: A measles vaccination coverage of 82% with the first dose at 9 months of age and 63% with the second dose (measles, mumps, and rubella) at 15 months was inadequate to block measles virus circulation in Taoyuan City in 1994. The city center, with a growing population, represents a high risk as an epicenter for measles outbreaks. Measles outbreaks may occur in a school population with 92% herd immunity.