Nosocomial transmission of measles to healthcare workers. Time for a national screening and immunization policy for NHS staff?

Implication of health care personnel in measles transmission

Healthcare personnel (HCP) play an important role in transmission of highly contagious diseases such as measles. Current immunization guidelines in Catalonia include Measles-Mumps-Rubella (MMR) immunization for HCP born after 1967 without evidence of immunity. Despite high vaccination coverage (90%) a high burden of measles cases related to outbreaks have occurred. The aim of this study was to assess the implication of HCP in measles transmission related to healthcare setting. A review of surveillance case data from 2001 to 2013 gathered through the Measles Elimination Program in Catalonia was performed. Twenty six outbreaks involving 797 cases were reported, 52 (6.5%) were HCP aged 21-41 years, 72,5% (38) patient were care personnel (doctors and nurses) and 22,5% (14) other health care related personnel. Forty six 87%) were unvaccinated, 4(10%) had only one dose and 2 had two doses of MMR. In community outbreaks 30 clusters with HCP involved were observed, yet none were identified as index cases. Non-vaccinated HCPs against measles were all under 45 years of age. Vaccination is the only reliable protection against nosocomial spread of measles from HCPs. Assessing vaccination status of HCPs and implementing a 2 dose vaccination in those lacking evidence of immunity is needed in order to set to zero the risk of acquiring and spreading measles in healthcare (HC) settings.

A global perspective of vaccination of healthcare personnel against measles: systematic review

Measles transmission has been well documented in healthcare facilities. Healthcare personnel who are unvaccinated and who lack other evidence of measles immunity put themselves and their patients at risk for measles. We conducted a systematic literature review of measles vaccination policies and their implementation in healthcare personnel, measles seroprevalence among healthcare personnel, measles transmission and disease burden in healthcare settings, and impact/costs incurred by healthcare facilities for healthcare-associated measles transmission. Five database searches yielded 135 relevant articles; 47 additional articles were found through cross-referencing. The risk of acquiring measles is estimated to be 2 to 19 times higher for susceptible healthcare personnel than for the general population. Fifty-three articles published worldwide during 1989-2013 reported measles transmission from patients to healthcare personnel; many of the healthcare personnel were unvaccinated or had unknown vaccination status. Eighteen articles published worldwide during 1982-2013 described examples of transmission from healthcare personnel to patients or to other healthcare personnel. Half of European countries have no measles vaccine policies for healthcare personnel. There is no global policy recommendation for the vaccination of healthcare personnel against measles. Even in countries such as the United States or Finland that have national policies, the recommendations are not uniformly implemented in healthcare facilities. Measles serosusceptibility in healthcare personnel varied widely across studies (median 6.5%, range 0-46%) but was consistently higher among younger healthcare personnel. Deficiencies in documentation of two doses of measles vaccination or other evidence of immunity among healthcare personnel presents challenges in responding to measles exposures in healthcare settings. Evaluating and containing exposures and outbreaks in healthcare settings can be disruptive and costly. Establishing policies for measles vaccination for healthcare personnel is an important strategy towards achieving measles elimination and should be a high priority for global policy setting groups, governments, and hospitals.

Prevalence of measles antibodies among health care workers in Catalonia (Spain) in the elimination era

BACKGROUND

Interruption of measles transmission was achieved in Catalonia (Spain) in 2000. Six years later, a measles outbreak occurred between August 2006 and June 2007 with 381 cases, 11 of whom were health care workers (HCW).The objective was to estimate susceptibility to measles in HCW and related demographic and occupational characteristics.

METHODS

A measles seroprevalence study was carried out in 639 HCW from six public tertiary hospitals and five primary healthcare areas. Antibodies were tested using the Vircell Measles ELISA IgG Kit. Data were analyzed according to age, sex, type of HCW, type of centre and vaccination history.The odds ratios (OR) and their 95% CI were calculated to determine the variables associated with antibody prevalence. OR were adjusted using logistic regression.Positive predictive values (PPV) and the 95% confidence intervals (CI) of having two documented doses of a measles containing vaccine (MCV) for the presence of measles antibodies and of reporting a history of measles infection were calculated.

RESULTS

The prevalence of measles antibodies in HCW was 98% (95% CI 96.6-98.9), and was lower in HCW born in 1981 or later, after the introduction of systematic paediatric vaccination (94.4%; 95% CI 86.4-98.5) and higher in HCW born between 1965 and 1980 (99.0%; 95% CI 97.0-99.8). Significant differences were found for HCW born in 1965-1980 with respect to those born in 1981 and after (adjusted OR of 5.67; 95% CI: 1.24-25.91).A total of 187 HCW reported being vaccinated: the proportion of vaccinated HCW decreased with age. Of HCW who reported being vaccinated, vaccination was confirmed by the vaccination card in 49%. Vaccination with 2 doses was documented in only 50 HCW, of whom 48 had measles antibodies. 311 HCW reported a history of measles.The PPV of having received two documented doses of MCV was 96% (95% CI 86.3-99.5) and the PPV of reporting a history of measles was 98.7% (95% CI 96.7-99.6).

CONCLUSIONS

Screening to detect HCW who lack presumptive evidence of immunity and vaccination with two doses of vaccine should be reinforced, especially in young workers, to minimize the risk of contracting measles and infecting the susceptible patients they care for.

Changes in measles seroepidemiology of healthcare workers in southern Taiwan

To assess the measles seroepidemiology of healthcare workers (HCWs), from 2004 to 2009 all newly recruited staff at a university hospital in Taiwan, were tested for specific immunoglobulin G antibodies for measles virus using enzyme-linked immunosorbent assays. A total of 1584 HCWs were included. The positivity rate of measles antibody for physicians and nurses was about 90%. The positivity of measles antibody in different age groups was 78·1%, 93·9% and 94·2% for 20-29, 30-39 and ≥40 years age groups, respectively. Equivocal results were more frequent in the 20-29 (17·1%) years age group. A lack of antibody against measles was reported for 66 (4·2%) of those tested. Medical student (8·3%) and housekeeping personnel (5·3%) had the greatest lack of antibodies. This study demonstrates the waning measles immunity in younger HCWs in Taiwan, which poses the potential risk of nosocomial transmission of measles. Periodic surveillance and revaccination of susceptible HCWs is recommended.

High seroprevalence of varicella, measles, mumps, rubella and pertussis antibodies in first-grade medical students

OBJECTIVE

The aim of the study was to investigate seropositivity for five vaccine-preventable communicable diseases - varicella, measles, mumps, rubella and pertussis - in a sample of first-grade medical students.

METHODS

A total of 256 students were tested for varicella IgG antibodies. In addition, 138 of the students were serologically screened for measles, mumps, rubella and pertussis antibodies. Data on vaccination and history of measles, mumps, rubella and pertussis were collected.

RESULTS

Immunity to varicella, measles, mumps and rubella was established in 97.6%, 96.4%, 97.8% and 99.3% participants, respectively. Anti-pertussis toxin antibodies were detected in 81.2% of the students.

CONCLUSIONS

The rates of varicella, measles, mumps and rubella immunity in first-grade medical students are very high. To identify those students who need vaccination before commencing practical work in healthcare facilities, a meticulous disease and vaccination history should be taken and medical records should be reviewed. Medical students providing no written evidence of adequate vaccination status should be serologically tested and vaccinated if necessary.

Healthcare workers and immunity to infectious diseases

OBJECTIVE

In 2002, New South Wales (NSW) Health introduced an updated policy for occupational screening and vaccination against infectious diseases. This study describes healthcare worker (HCW) immunity to hepatitis B, measles, mumps, rubella (MMR) and varicella based on serological screening, following introduction of this policy.

METHODS

HCW screening serology performed at two healthcare facilities in south western Sydney (Bankstown and Fairfield) was extracted for the period September 2003 to September 2005. Immunity to hepatitis B, MMR and varicella was quantitated and cross-tabulated against age, sex and staff risk category.

RESULTS

A total of 1,320 HCWs were screened. Almost two thirds were immune to hepatitis B while immunity to MMR and varicella ranged from 88% to 94%. Age stratification showed lower levels of measles immunity in those born after 1965.

CONCLUSIONS

Despite availability of vaccination for over two decades, a significant proportion of HCWs at these two facilities were non-immune to hepatitis B. This is of concern for those non-immune staff involved in direct clinical care, who are at risk of blood and body fluid exposures. The small group of HCWs non-immune to MMR and varicella pose a risk to themselves and others in the event of an outbreak.

IMPLICATIONS

There is a need for improved implementation of the occupational screening and vaccination policy, including better education of HCWs about the risks of non-immunity to vaccine preventable diseases. The revised 2007 NSW Health policy may assist this process and will need evaluation to determine whether HCW immunity improves in the coming years.

Specific immunization issues in the occupational health setting

This article looks at the components of an effective occupational health vaccination programme and also reviews the legal basis for them. It addresses the issue of vaccine licensing including pre-clinical, clinical and post-licensing studies. It explores screening for vaccine preventable diseases in the occupational health setting and then addresses particular issues around hepatitis B, chicken pox, tuberculosis, measles, rubella, diphtheria, polio, mumps and hepatitis A.

Exposure of Ugandan health personnel to measles and rubella: Evidence of the need for health worker vaccination

With rubella and, until recently, measles highly endemic in Uganda, health personnel are at risk of these vaccine-preventable diseases and a source of transmission to patients. Measles and rubella serology (IgG) and history of exposure and vaccination were determined among 311 health care workers in a nationwide study. All tested positive for measles IgG, whereas 49.2% reported having been vaccinated. Rubella antibodies were present in 98.1% of personnel; 3.2% of women of child-bearing age were still susceptible. Increasing age and longer duration of service increased the risk of rubella infection. A national policy on health worker protection should include immunisation against vaccine-preventable diseases upon entry to training.

Measles outbreak in young adults in Victoria, 1999

OBJECTIVES

To describe an outbreak of measles in Victoria.

DESIGN

Case series with cases identified through enhanced passive surveillance and outbreak-related active surveillance.

SETTING

State of Victoria, 1999.

MAIN OUTCOME MEASURES

Number of cases; epidemiological links and patterns of transmission; patient demographic features and vaccination status; complications.

RESULTS

75 cases were identified (74 laboratory-confirmed; and one epidemiologically linked to a laboratory-confirmed case), with onset between 11 February and 2 May 1999. The first case was in a 21-year-old woman who had recently holidayed in Bali and worked at a large cinema complex in Melbourne. Sixteen cases occurred in people who had contact with the index case at the cinema on one evening. The outbreak spread to regional Victoria and South Australia. Median age of patients was 22 years; 64 (85%) were born between 1968 and 1981, with only one patient in the age group targeted by the primary school component of the 1998 Australian Measles Control Campaign; this child had not been vaccinated. More than a third of patients (28) were hospitalised (total, 97 inpatient days), and five were healthcare workers.

CONCLUSIONS

This outbreak was caused by international importation of measles virus. It highlights the change in epidemiology of measles in Australia, from a disease of childhood to one predominantly affecting young adults. A strong two-dose childhood vaccination program, vigilant surveillance, and rapid response to outbreaks will continue to be the basis of measles control, but better protection for young adults should be considered.