This study aimed to perform a comparative analysis between the frequency of detection of the measles virus in Bulgarian patients by using two types of laboratory methods - serological and molecular. Materials and Methods: The total 202 patients with two types of clinical material (serum samples and nasal swabs) were tested. The specimens were collected during the measles outbreak in Bulgaria in 2019. The serological - indirect EIA test for detection of specific IgM antibodies and molecular methods - extraction and detection of viral RNA were used. Results: In the present study, tested Bulgarian patients were divided into 11 age groups. The majority of patients were under 9 years of age (126/202, 62%), including children under 1 years of age (31/202, 15%).  Acute measles infection was confirmed by ELISA-IgM in 136/202(67%) and by RT-PCR in 138/202 (68%) of cases. The positive patients detected only by PCR methods are mainly in younger tested. In 123/202 of the patients (60,89%) measles infection was confirmed by a combined serological and molecular-biological approach. The coincidence percentage rate of results obtained is 87%, including double positive (n=123) and double negative (n=52) tests. No significant differences in the results in terms of gender and age were found. Conclusion: The combined  laboratory approach (immunoenzymatic and molecular assay of each  suspected case) is a requisite for measles detection, especially before the onset of symptoms when specific Ig M antibodies could not be detected. Molecular biological techniques are basic and preferred approach in the field of modern biomedical sciences.  They play an important role in the early and accurate etiological diagnosis and monitoring of viral infections, in particular the measles virus.

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Background: Healthcare workers are at greater risk of acquiring measles than the general population. Transmission occurs from infected patients to staff and from infected staff to patients and colleagues. In inpatient and outpatient settings, susceptible patients suffering from other conditions, especially the elderly and severely ill patients in intensive care units are at a high risk of severe disease or death if infected with measles. The most effective preventive measure against measles is vaccination with two doses of a measles-containing vaccine. Aim: To perform a serological assessment of the presence of measles IgG antibodies among healthcare workers. Materials and Methods: The present study involves serological testing performed on samples from persons working in hospitals and Regional Health Inspectorates in the country. Screening started in connection with a reported measles outbreak in Bulgaria in 2019, and continued into early 2020. An indirect ELISA assay for the detection of specific measles IgG antibodies in serum samples was used. Results: The tested 152 healthcare workers were from 5 regions of the country, i.e. Sofia-capital (n=87), Burgas (n=6), Blagoevgrad (n=5), Dobrich (n=8) and Pazardzhik (n=46). Anti-measles IgG antibodies were detected in 85.5% of the participants (130/152). Negative results, indicating a possible lack of protective immunity against measles, were obtained primarily in samples from persons younger than 40 years of age. Conclusion: Screening to identify healthcare workers who lack presumptive evidence of protective immunity against measles should be reinforced, especially among younger healthcare workers, in order to minimize the risk of measles both among healthcare workers and among patients.

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Background: Healthcare workers (HCWs) are at increased risk of exposure to many viral infections, including vaccine preventable diseases (VPDs) such as measles, mumps and rubella (MMR) as compared to non-HCWs. Immunity of HCWs against these viruses is mandatory in a healthcare setting due to possible exposure from patients or colleagues. Aim: To provide an assessment of anti-measles, mumps and rubella IgG seropositivity among Bulgarian HCWs employed in hospitals and regional health inspectorates (RHI), as an indicator of protective immunity against MMR in this risk group.  Materials and Methods: In the current study, 181 HCWs from Infectious Units in regional hospitals in the country, and HCWs from the RHI, involved in the monitoring and surveillance of MMR cases in Bulgaria were screened. Serum specimens from all participants were tested by a commercial indirect enzyme-linked immunosorbent assay (Anti-Measles, Anti-Mumps, Anti-Rubella IgG EIA-Euroimmun®, Germany) for presence of IgG antibodies against measles, mumps and rubella, as an indicator of protective immunity.  Results: The study included 181 HCWs, 25 male and 156 female, aged 22 to 66 years. The average protective seroprevalence for measles, mumps and rubella was 82.9%, 76.2% and 92.3% percent, respectively. The highest share of negative results were obtained for mumps-specific IgG – 23.2% (42/181), followed by measles 16.6% (60/181) and rubella-specific IgG 7.7% (19/181). Regarding the age distribution, the highest number of HCWs non-immune to measles and mumps was found among the 31- 40-year olds, and against mumps – among the 41-50-year-olds. Conclusion: HCWs are at greater risk of contracting infections than the general population because of contact with sick patients or infectious material. Infected healthcare workers can spread nosocomial diseases to vulnerable patients with more severe illness, leading to complications and even death. Therefore, the vaccination status of HCWs must be strictly monitored.