Preliminary findings indicate nosocomial transmission and Roma population as most affected group in ongoing measles B3 genotype outbreak in Bulgaria, March to August 2017.

From March to August 2017, 165 measles cases were reported from three regions in Bulgaria. The age range was 0-55 years and 66% of the cases were under 9 years. The Roma population was disproportionally affected (89% of cases), 41% cases were unvaccinated and in 24 cases there was nosocomial transmission mostly in paediatric departments. A child under 12 months of age died. Control measures have been taken and the investigation is still ongoing.

The measles outbreak in Bulgaria, 2009-2011: An epidemiological assessment and lessons learnt.

Measles re-emerged in a nationwide outbreak in Bulgaria from 2009 to 2011 despite reported high vaccination coverage at national level. This followed an eight-year period since the last indigenous cases of measles were detected. The Bulgarian National Centre of Infectious and Parasitic Diseases collated measles surveillance data for 2009-2011. We analysed data for age group, sex, ethnicity, diagnosis confirmation, vaccination, hospitalisation, disease complications, and death and describe the outbreak control measures taken. The outbreak started in April 2009 following an importation of measles virus and affected 24,364 persons, predominantly Roma. Most cases (73%) were among children < 15 years old. Vaccination status was available for 52% (n = 12,630) of cases. Of children 1-14 years old, 22% (n = 1,769) were unvaccinated and 70% (n = 5,518) had received one dose of a measles-containing vaccine. Twenty-four measles-related deaths were reported. The Roma ethnic group was particularly susceptible to measles. The magnitude of the outbreak resulted primarily from the accumulation of susceptible children over time. This outbreak serves as a reminder that both high vaccination coverage and closing of immunity gaps across all sections of the population are crucial to reach the goal of measles elimination.

Comparison of rubella seroepidemiology in 17 countries: progress towards international disease control targets.

OBJECTIVE: To standardize serological surveillance to compare rubella susceptibility in Australia and 16 European countries, and measure progress towards international disease-control targets. METHODS: Between 1996 and 2004, representative serum banks were established in 17 countries by collecting residual sera or community sampling. Serum banks were tested in each country and assay results were standardized. With a questionnaire, we collected information on current and past rubella vaccination programmes in each country. The percentage of seronegative (< 4 IU/ml) children (2-14 years of age) was used to evaluate rubella susceptibility, and countries were classified by seronegativity as group I (< 5%), group II (5-10%) or group III (> 10%). The proportion of women of childbearing age without rubella protection (< or = 10 IU/ml) was calculated and compared with WHO targets of < 5%. FINDINGS: Only Romania had no rubella immunization programme at the time of the survey; the remaining countries had a two-dose childhood schedule using the measles, mumps and rubella (MMR) vaccine. The percentage of susceptible children defined five countries as group I, seven as group II and four as group III. Women of childbearing age without rubella protection were < 5% in only five countries. CONCLUSION: Despite the low reported incidence in many countries, strengthening the coverage of the routine two-dose of MMR vaccine among children is needed, especially in group III countries. Catch-up campaigns in older age groups and selective targeting of older females are needed in many countries to ensure necessary levels of protective immunity among women of childbearing age.

Subacute sclerosing panencephalitis in Bulgaria (1978-2002).

The epidemiology of subacute sclerosing panencephalitis (SSPE) has changed substantially since the introduction of measles vaccine. We studied the incidence of SSPE in Bulgaria based on cases admitted to the Child Neurology Clinic, University Hospital of Neurology and Psychiatry, Sofia, for a 25-year period (1978-2002). The SSPE incidence prior to and during the period of routine measles immunization was analyzed. SSPE was diagnosed in 40 children (29 males and 11 females, mean age 8.5 years), 28 from 1978 to 1984 (average 4 patients/year), and 12 from 1995 to 2002 (average 1.7 patients/year). Thirty-eight cases (95%) were non-immunized and had early measles infection. Age at onset of SSPE ranged from 8 to 11 years (52.5%) with a mean latent period of 7 years following measles infection. The increase in SSPE incidence (1995-2002) following a 10-year disease-free period (1985-1994) appears to be related to early measles infection (mean age 11 months) during the measles epidemic of 1991-1992. During the period 1995-2002, children had earlier measles infection (average 11 months) and earlier onset of SSPE (mean age 8.4 years) than in the period 1978-1984 (mean age at measles infection 18 months, and of SSPE onset 11.2 years). The SSPE incidence in Bulgaria during the 25-year period from 1978 to 2002 confirms the importance of early measles infection as a risk factor for SSPE, and the role of routine measles immunization in SSPE prevention.

Clinical and epidemiological characteristics of subacute sclerosing panencephalitis in Bulgaria during the past 25 years (1978-2002).

The aims of the present study are to establish the subacute sclerosing panencephalitis (SSPE) incidence in Bulgaria for the 25-year period 1978-2002; to analyze the SSPE incidence prior to, and in the period of, routine measles immunization; and, to analyze the clinical characteristics of SSPE. SSPE was diagnosed in a total of 40 children; 28 of were diagnosed between 1978 and 1984, and 12 between 1995 and 2002. Thirty-eight cases (95%) were non-immunized and have had an early measles infection (mean age 16 months). The SSPE onset occurred primarily between 8 and 11 years of age (52.5%) with a mean latent period of about 7 years after the measles infection. After the 10-year disease-free period (1985-1994), the SSPE incidence increased between 1995 and 2002 because of the 1991-1992 measles epidemic. During the period 1995-2002 children with earlier measles infection and earlier SSPE onset predominated, compared to the period 1978-1984. The initial clinical manifestations included intellectual deterioration in 35%, extrapyramidal hyperkinesias in 29%, epileptic seizures in 15%, hemiparesis in 10%, and visual disturbances in 10% of the cases. Nine children (22.5%) demonstrated an atypical onset. A rapidly progressive course was observed in 4 children (10%) and a chronic progressive course with pseudoremissions over 2 years-in 8 cases (20%). Our analysis of the SSPE incidence in Bulgaria for the 25-year period (1978-2002) supports the importance of early measles infection as a crucial risk factor for this persistent neuroinfection. Moreover, it confirms the role of routine measles immunization in SSPE prevention.

Childhood bacterial meningitis in Bulgaria: a population-based retrospective study in six regions during 1992-96.

OBJECTIVES: We conducted a study to provide information on the importance of bacterial pathogens causing childhood meningitis in Bulgaria. METHODS: A 5-year population-based retrospective survey for bacterial meningitis in children <5 years of age was performed at all hospitals in the six largest regions of Bulgaria. RESULTS: There were 297 cases of meningitis reported, of which 211 (71.0%) were classified as bacterial in origin. The most common causes were Neisseria meningitidis (49 cases) and Haemophilus influenzae type b (Hib) (44 cases), accounting for 36% and 32% of etiologically confirmed cases. Thirty-one cases (70.5%) of Hib meningitis occurred in children <2 years of age, and 26 (59.1%) occurred in children 6-23 months of age. Average annual incidence rates of Hib meningitis based on the population of children <5 years of age for each region ranged from 1.3 to 9.8 per 100,000 (mean 5.9/100,000). CONCLUSION: The estimated incidence rates from this study were similar to those reported from southern European and Mediterranean countries. Further studies are planned to provide information on appropriate strategies for preventing childhood meningitis in Bulgaria.

Epidemiology of meningitis due to Haemophilus influenzae type b in children in Bulgaria: a prospective, population-based surveillance study.

OBJECTIVE: To assess the incidence of meningitis caused by Haemophilus influenzae type b (Hib) among children in Bulgaria and to provide evidence for an informed decision on the use of Hib vaccines in Bulgaria. METHODS: From 1 July 1997 to 31 December 1999, active surveillance for meningitis was conducted in six regions. For children with suspected meningitis, a cerebrospinal fluid (CSF) specimen was sent for cytology, chemistry, latex agglutination testing, culture and sensitivity. FINDINGS: During the 2.5-year study period, surveillance was conducted among 138 249 children aged <5 years - a sample representing 40% of all Bulgarian children in this age group. Overall, 285 children with suspected meningitis were identified. In eight children, clinical symptoms of meningitis resolved rapidly before a CSF specimen could be obtained. Of the remaining 277 children, 121 (44%) were classified as having probable bacterial meningitis on the basis of a CSF examination. An organism was identified for 88 (73%) of the 121 cases with probable bacterial meningitis. There were 21 cases of Hib, giving a mean annual incidence of 6.1 Hib meningitis cases per 100 000 children <5 years; the case-fatality rate was 10%. Nearly 60% of Hib isolates were resistant to one or more antibiotics, but they were not resistant to third-generation cephalosporins. CONCLUSION: On the basis of these findings, Hib conjugate vaccines have been included in the list of vaccines recommended for children by the Bulgarian Ministry of Health. The recommended initial treatment for paediatric bacterial meningitis has been changed to third-generation cephalosporins.