A Report on the Large Measles Outbreak in Lyon, France, 2010 to 2011

Saturday, 15th of September 2012

• A report on the large measles outbreak in Lyon, France, 2010 to 2011

Eurosurveillance, Volume 17, Issue 36, 06 September 2012

Surveillance and outbreak reports

Abstract and conclusions are below; full text is at http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20264 

In 2010 and 2011, the city of Lyon, located in the Rhône-Alpes region (France), has experienced one of the highest incidences of measles in Europe. We describe a measles outbreak in the Lyon area, where cases were diagnosed at Lyon University hospitals (LUH) between 2010 and mid-2011. Data were collected from the mandatory notification system of the regional public health agency, and from the virology department of the LUH. All patients and healthcare workers who had contracted measles were included. Overall, 407 cases were diagnosed, with children of less than one year of age accounting for the highest proportion (n=129, 32%), followed by individuals between 17 and 29 years-old (n=126, 31%). Of the total cases, 72 (18%) had complications. The proportions of patients and healthcare workers who were not immune to measles were higher among those aged up to 30 years. Consequently, women of childbearing age constituted a specific population at high risk to contract measles and during this outbreak, 13 cases of measles, seven under 30 years-old, were identified among pregnant women. This study highlights the importance of being vaccinated with two doses of measles vaccine, the only measure which could prevent and allow elimination of the disease.

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Discussion and conclusion

It was estimated in 2009 that eight percent of people aged between six and 29 years were not immunised against measles in France [12]. The coverage is under the threshold of 95% needed for measles elimination [13]. The objective of this study was to describe the measles outbreak which occurred in Lyon, located in the Rhône-Alpes area, from 2010 to mid 2011. Our analysis focused on patients diagnosed with measles in LUH, pregnant women and HCW, and on virology and immunology data from the hospital virology-based surveillance. Overall, 407 cases of measles were diagnosed in LUH. According to 2009 estimations 92 percent of individuals between six and 29 years-old were immunised in France [12]. Moreover,  in 2010–2011, the vaccination coverage for measles at 24 months-old (1 dose) was 88.8% in the Rhône-Alpes region [11]. Consequently, IgG seropositivity rates among children and young adults under 30 years-old in the Rhone-Alpes region but also nationwide are likely to reflect more vaccination coverage than contact with the virus. Although the tested population was a biased sample of the Lyon population, seroprevalence of IgG against measles was low, especially in patients and HCW under 30 years. Vaccination against measles is recommended but not mandatory for HCW in France. Their risk to contract measles appears to be much higher than the general population and they can potentially transmit the disease to their patients, especially the immunocompromised ones [14]. It appears urgent to reach a higher vaccination coverage with two doses in the French population. Eliminating measles is one of the World Health Organization’s goal, which is expected for 2015 [15]. According to the results of our study, overall 78% of the measles cases were not vaccinated. A report based on French mandatory notifications between January 2008 and April 2011 [2] found similar rates concerning lack of vaccination: 86% of the cases did not receive the measles, mumps, and rubella (MMR) vaccine against measles, with differential compliance and immunisation coverage in the various districts of France. It pointed out that communications towards the general population about the need to be vaccinated in order to be protected, have to be strengthened.

Attention must be paid to newborns under one year of age because they are too young to be vaccinated and may no longer be protected by maternal antibodies. At the age of six months, 90% of the infants are not protected, irrespective of the mother’s immunisation status [16]. Measles acquired during pregnancy can have deleterious effect on the mother and child outcome [17]. The most serious and frequent complication reported for pregnant women is pneumonia [17-20]. The hospitalisation and case fatality rates among pregnant women may be higher than among non-pregnant adults [20]. Concordant with these data, four cases of pneumonia among 13 pregnant cases were found in our study. Six of the pregnant women were hospitalised. An increased risk of foetal and neonatal loss is also reported [17-20]. In one case observed in this study, a premature birth occurred, however it could have been attributable to other causes. Some authors also reported an increased risk of subacute sclerosing panencephalitis following neonate [21] or congenital [22] measles infection. Women in childbearing age should be informed of the risk of contracting measles and its possible complications. Vaccination that can only assure protection should be proposed as soon as possible in pre- or post-partum. Measles among pregnant women should be no longer considered uncommon in the regions that report outbreaks and should be systematically considered in the context of pregnant women presenting to a health practitioner with pneumonia. 

In comparison with other European countries, France has been the most affected with 13,957 cases reported between January and August 2011 [9]. Italy, who reported 4,300 measles cases during the same period was the second most affected European country [6]. Four measles cases among pregnant women were reported [6] and 36% of cases were hospitalised. Overall 14% presented complications [6], which was in concordance with the complication rate of 18% in the Lyon area. Romania also experienced a large measles outbreak in 2011, with 2,072 reported cases [8]. The complication rate in Romania was much higher than in the Lyon area (respectively, 39% and 18%). Finally, the Geneva canton in Switzerland, which neighbours the Rhône-Alpes region, only reported 41 measles cases between January and May 2011, so it was far less affected than Rhône-Alpes area [5]. There, serious control measures, with quarantining and a vaccination campaign were systematically implemented. The larger number of cases that we experimented during the outbreak in Lyon area did not prevent carrying out a vaccination campaign, however, quarantining each measles case was more difficult to implement.

The main limitation of our study was a possible underestimation of the true measles incidence, as, in France, about 50% of measles cases were not reported on mandatory notification [10]. However this should not bias time-trends. Moreover, we were unable to calculate its incidence per 1,000 inhabitants because the exact origin of individuals was not known.

In conclusion, catch-up vaccination campaigns should focus on individuals aged under 30 years-old who have not received two doses of measles vaccine and on HCW. The outbreak is likely to re-occur, especially in the regions of France with low vaccine coverage. Clusters of susceptible individuals accrued over the years [10,11]. Indeed, the French Institute for Public Health Surveillance (InVS) reported that among children of 24 months old in 2008, only 90% had received one dose of the measles vaccine while according to the French vaccination programme, they should have already got two doses [23]. A fourth epidemic wave has to be expected in France and Europe. Hospital-based surveillance of measles is relevant to estimate the spread of the disease in the community and to help with early detection of healthcare-acquired cases.

Acknowledgements
We thank the Agence Régionale de Santé de Rhône-Alpes (AM McKenzie, G Courbis) for their contribution to our surveillance of measles cases at Lyon University Hospitals. We thank F Champion, A Fichez, S Blanc, K Bellemin, C Volckmann, A Duvermy, MA Denis, P Nargues, JB Fassier, for their contribution to the hospitalised-based surveillance of measles cases. Manuscript editing by Ovid Da Silva is acknowledged.

References

1. Haut Conseil de la santé publique (HCSP). Avis relatif à l’actualisation des recommandations vaccinales contre la rougeole pour les adultes. 11 février 2011. [Notice on update of recommendations for measles vaccinations in adults]. Paris: HCSP; 11 Feb 2011. French.
2. Baudon C, Parent du Châtelet I, Antona D, Freymuth F, Poujol I, Maine C, et al. Caractéristiques de l’épidémie de rougeole démarrée en France depuis 2008 : bilan des déclarations obligatoires pour les cas survenus jusqu’au 30 avril 2011. [Characteristics of the measles epidemic in France which began in 2008: a review of mandatory reporting for cases occuring until 30 April 2011]. Bull Epidémiol Hebd. 2011;33-34:353-8. French.
3. Benkimoun P. Outbreak of measles in France shows no signs of abating. BMJ. 2011;342:d3161.
4. Six C, Blanes de CJ, Duponchel J, Lafont E, Decoppet A, Travanut M, et al. Spotlight on measles 2010: Measles outbreak in the Provence-Alpes-Cote d'Azur region, France, January to November 2010 - substantial underreporting of cases. Euro Surveill. 2010;15(50):pii=19754. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19754
5. Delaporte E, Richard JL, Wyler Lazarevic CA, Lacour O, Girard M, Ginet C, et al. Ongoing measles outbreak, Geneva, Switzerland, January to March 2011. Euro Surveill. 2011;16(10):pii=19815. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19815
6. Filia A, Tavilla A, Bella A, Magurano F, Ansaldi F, Chironna M, et al. Measles in Italy, July 2009 to September 2010. Euro Surveill. 2011;16(29):pii=19925. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19925
7. Sabbe M, Hue D, Hutse V, Goubau P. Measles resurgence in Belgium from January to mid-April 2011: a preliminary report. Euro Surveill. 2011;16(16):pii=19848. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19848
8. Stanescu A, Janta D, Lupulescu E, Necula G, Lazar M, Molnar G, et al. Ongoing measles outbreak in Romania, 2011. Euro Surveill. 2011;16(31):pii=19932. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19932
9. European Centre for Disease Prevention and Control (ECDC).Surveillance report. European monthly measles monitoring. Stockholm: ECDC. Sep 2011. Available from: http://ecdc.europa.eu/en/publications/Publications/111018_EMMO_SEPT_2011.pdf
10. Parent du Châtelet I, Antona D, Freymuth F, Muscat M, Halftermeyer-Zhou F, Maine C, et al. Spotlight on measles 2010: update on the ongoing measles outbreak in France, 2008-2010. Euro Surveill. 2010;15(36):pii=19656. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19656
11. Dennetiere G, Fort B. Rougeole en Rhône-Alpes. Point sur la vague épidémique d’octobre 2010 à septembre 2011. [Measles in Rhône-Alpes. Sum up on the situation regarding the epidemic wave from October 2010 to September 2011]. Bulletin de veille sanitaire Rhône-Alpes. Numero special rougeole. 14 Nov 20122. French. Available from: http://www.invs.sante.fr/Publications-et-outils/Bulletin-de-veille-sanitaire/Tous-les-numeros/Rhone-Alpes/Bulletin-de-veille-sanitaire-Rhone-Alpes.-Numero-special-rougeole
12. Lepoutre A, Antona D, Fonteneau L, Baudon C, Halftermeyer-Zhou F, Le Strat Y, et al. Enquête nationale de séroprévalence des maladies infectieuses 2009-2010, 1er résultats. Communication orale, 12ème Journées Nationales d’Infectiologie, Toulouse 2011. [National seroprevalence survey of infectious diseases 2009-2010, the first results. Oral communication, 12th National Symposium on Infectious Diseases, Toulouse 2011]. Med Mal Inf. 2011;41(6):suppl.1. French.
13. Centers for Disease Control and Prevention (CDC). Increased transmission and outbreaks of measles — European Region, 2011. MMWR Morb Mortal Wkly Rep. 2011;60(47):1605-10.
14. Botelho-Nevers E, Cassir N, Minodier P, Laporte R, Gautret P, Badiaga S, et al. Measles among healthcare workers: a potential for nosocomial outbreaks. Euro Surveill. 2011;16(2):pii=19764. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19764
15. World Health Organization (WHO) – Regional office for Europe. Eliminating measles and rubella. Framework for the verification process in the WHO European Region. 2012. WHO Regional Office for Europe: Copenhagen; 2012. Available from: http://www.euro.who.int/__data/assets/pdf_file/0003/158304/EURO_MR_Elimin_Verification_Processv2.pdf
16. Gagneur A, Pinquier D. Letter to the editor. Spotlight on measles 2010: timely administration of the first dose of measles vaccine in the context of an ongoing measles outbreak in France. Euro Surveill. 2010;15(41):pii=19689. Available from: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19689
17. Manikkavasagan G, Ramsay M. The rationale for the use of measles post-exposure prophylaxis in pregnant women: a review. J Obstet Gynaecol. 2009;29(7):572-5.
18. Ali ME, Albar HM. Measles in pregnancy: maternal morbidity and perinatal outcome. Int J Gynaecol Obstet. 1997;59(2):109-13.
19. Chiba ME, Saito M, Suzuki N, Honda Y, Yaegashi N. Measles infection in pregnancy. J Infect. 2003;47(1):40-4.
20. Eberhart-Phillips JE, Frederick PD, Baron RC, Mascola L. Measles in pregnancy: a descriptive study of 58 cases. Obstet Gynecol. 1993;82(5):797-801.
21. Sawaishi Y, Abe T, Yano T, Ishikawa K, Takada G. SSPE following neonatal measles infection. Pediatr Neurol. 1999;20(1):63-5.
22. Cruzado D, Masserey-Spicher V, Roux L, Delavelle J, Picard F, Haenggeli CA. Early onset and rapidly progressive subacute sclerosing panencephalitis after congenital measles infection. Eur J Pediatr. 2002;161(8):438-41.
23. Institut de Veille Sanitaire (InVS). Couverture vaccinale rougeole: La couverture vaccinale à 24 mois. [Measles vaccination coverage among infants aged 24 months-old]. Paris: InVS. 13 Apr 2010. French. Available from: http://www.invs.sante.fr/Dossiers-thematiques/Maladies-infectieuses/Maladies-a-declaration-obligatoire/Rougeole/Couverture-vaccinale-rougeole