Combined MMR Vaccine in Childhood Measles

Transcription

1 Combined MMR Vaccine in Childhood Measles Introduction This fact box will help you to weigh the benefits and harms of the combined vaccine against measles, mumps and rubella (MMR). The focus of this fact box is on measles. The information and numbers do not represent a conclusive evaluation. They are based on the best scientific evidence currently available. This fact box was developed by the Harding Center for Risk Literacy. What is measles? What is a combined MMR vaccine? Who might consider the combined MMR vaccine? Measles is a highly contagious communicable disease caused by a virus. In the first phase of the disease, symptoms may include fever, coughing, rhinitis, inflamed conjunctiva (sore, red eyes) and small white spots on the inside of the cheeks. In the second phase, a characteristic red blotchy rash develops. Even a short direct contact with contagious secretions from the throat or the nose (by touching contaminated objects) leads to an infection with the virus, which can also be spread through airborne droplets when infected people cough, sneeze or speak [4]. The vaccination against measles is usually administered as a combined vaccine against measles, mumps and rubella; thus the abbreviation MMR [4]. Infants aged 11 to 14 months may receive the first dose of the combination vaccine. The second vaccination is a cautionary measure in case the first vaccination did not lead to the development of immunity. The second dose follows usually between the ages of 15 and 23 months, or at the earliest four weeks after the first vaccination and at the latest at the end of the second year of age. Furthermore, all adults born after 1970 who have not been vaccinated, who have been vaccinated just once or whose vaccination status is unknown may still consider a onceonly combined MMR vaccination [4].

2 Combined MMR Vaccine in Childhood Measles Numbers for children 12 months and older with regard to potential virus exposure later in life. A full vaccination series during childhood can protect from an infection in case of exposure to the measles virus later in life, or from a severe course of the disease despite vaccination. Further, contact with the virus becomes less frequent in a population with high rates of inoculation and thus prevents spreading of the virus (herd immunity). Redness, swelling or pain at the injection site are possible; however, severe reactions to the vaccination are very rare. Benefits* How many people contract measles? How many people suffer from fever caused by measles? How many people suffer from pneumonia caused by measles? How many people suffer from inflammation of the brain (encephalitis) caused by measles? How many people die from measles? people without vaccination exposed to the measles virus people with vaccination exposed to the measles virus Harms** How many children suffer from low platelet count (thrombocytopenia) due to the vaccination? How many children suffer from febrile seizure due to the vaccination? *The combined MMR vaccination also protects from mumps and rubella. Numbers given under benefits are based on model calculations. **Redness, pain or swelling at the injection site are possible. Sources: [1] Demicheli et al. Cochrane Database Syst Rev 2012;2:CD [2] Doerr & Gerlich. Georg Thieme 2010.[3] Plotkin et al. Vaccines. 6 ed: Saunders [4] Robert Koch-Institut (Ed.). RKI-Ratgeber für Ärzte: Masern [5] Wichmann & Ultsch. Bundesgesundheitsbl-Gesundheitsforsch-Gesundheitssch 2013;56(9): [6] Friese K et al. (Ed.). Infektionserkrankungen der Schwangeren und des Neugeborenen. Springer [7] Quast & Stück. Ärzte Merkblatt [8] Black et al. Br J Clin Pharmacol 2003;55(1): [9] Patja et al. Pediatrics 2001;107(2):e27. [10] Vestergaard et al. JAMA 2004;292(3): [11] Wilson et al. PLoS One 2011;6(12):e Last update: April 2016

3 What does the fact box show? The fact box shows the benefits and harms of combined MMR vaccine for people with vaccination in their childhood compared to people without vaccination in case of exposure to the measles virus. The table may be read as follows: If people who had not been vaccinated against measles, whether as a child or an adult, were exposed to the measles virus, would be expected to be infected with measles. However, of vaccinated people, between 93 and 745 would become sick with measles after exposure to the virus. If people who had neither been vaccinated as a child, nor as an adult, were exposed to the measles virus, would be expected to suffer from fever caused by measles. Of vaccinated people, between 91 and 730 would suffer from fever caused by measles after exposure to the virus. The numbers in the fact box are rounded. For the benefits, the numbers are based on model calculations. These offset the probabilities of infections, symptomatic diseases and frequencies of symptoms in consideration of the effectiveness of the vaccine. What other aspects should be considered? If people who had not been vaccinated against measles whether as a child or an adult, came into contact with the measles virus, between 93 and 559 would suffer from pneumonia caused by measles. In contrast, of vaccinated people, 1 to 45 would suffer from pneumonia caused by measles. There is no connection between the MMR vaccine and autism. The study claiming this link published in 1998 has been proven a fake. Allergical reactions due to the MMR vaccine are very rare. Children with a severe allergy to eggs should be vaccinated under special monitoring. The fact box contains model calculations of the possible benefits and harms that may be expected in case of exposure to the measles virus. The probability of contact to a virus depends on many factors. The frequency of exposure to the virus depends on many factors, for example, the propagation of the rubella virus and the proportion of vaccinated people. Widespread vaccination additionally provides protection for people who may not normally be vaccinated (herd immunity). This population, which includes people with weakened immune systems and pregnant women, benefits from the slower spread of the virus. Therefore, the World

4 Health Organization (WHO) aims at a global vaccination rate of 95 out of every 100 children. It should be considered that a complete immunization series requires two doses of the vaccine. The combined MMR vaccine also protects from mumps and rubella. The vaccine is also available in combination with chickenpox (varicella-zoster virus) as a MMR+V vaccine. An individual vaccine against measles is hardly available anymore [4]. Quality of evidence Sources The overall evidence is of moderate quality. On the one hand, the contagion indices (proportion of those exposed to the rubella virus who become infected) and manifestation indices (proportion of those infected by the rubella virus who are symptomatic) have not been researched with adequate randomised controlled trials. On the other hand, the order of magnitude of the effectiveness of the vaccine has been validated among various populations across different study designs. Thus, at least the reduction of disease symptoms among vaccinated people versus unvaccinated people is documented with evidence. Information within the fact box were obtained from the following sources: Data based on clinical practice are missing, e.g. information from physicians and course books regarding the prevalence (frequency) of this disease, the contagion and manifestation indexes as well as current patient studies. Data based on clinical practice only partly correspond to the current vaccines and to the current health conditions of the German and Swiss populations [1-6]. The data on febrile seizure are based on cohort with, respectively, 456,000 and 537,000 children aged 12 to 23 months. The vaccine contained the vaccination strain Jeryl-Linn. The data on low platelet count (thrombocytopenia) are based on a patient control study with 139 children aged 13 to 24 months. On the effectiveness of the vaccine: [1] Demicheli V, Rivetti A, Debalini MG et al. Vaccines for measles, mumps and rubella in children. Cochrane Database Syst Rev 2012;2:CD [2] Doerr HW, Gerlich WH. Medizinische Virologie: Grundlagen, Diagnostik, Prävention und Therapie viraler Erkrankungen. Georg Thieme [3] Plotkin S, Orenstein W, Offit P. Vaccines. ed. WB Saunders Co 2012.

5 [4] Robert Koch-Institut. RKI-Ratgeber für Ärzte: Masern. 2014; EpidBull/Merkblaetter/Ratgeber_Masern.html, Access date 22 Aug [5] Wichmann PD, Ultsch B. Effektivität, Populationseffekte und Gesundheitsökonomie der Impfungen gegen Masern und Röteln. Bundesgesundheitsblatt-Gesundheitsforschung-Gesundheitsschutz 2013;56(9): On the risks of infections and of symptomatic disease progress in case of infections [2] Doerr HW, Gerlich WH. Medizinische Virologie: Grundlagen, Diagnostik, Prävention und Therapie viraler Erkrankungen. Georg Thieme [3] Plotkin S, Orenstein W, Offit P. Vaccines. 6 ed: Saunders [4] Robert Koch-Institut. RKI-Ratgeber für Ärzte: Masern. 2014; EpidBull/Merkblaetter/Ratgeber_Masern.html, Access date 22 Aug [6] Friese K, Mylonas I, Schulze A (Eds.). Infektionserkrankungen der Schwangeren und des Neugeborenen. Springer [7] Quast U, Stück B. Deutsches Grünes Kreuz (Ed.). Ärzte Merkblatt On the symptoms in case of infections: [2] Doerr HW, Gerlich WH. Medizinische Virologie: Grundlagen, Diagnostik, Prävention und Therapie viraler Erkrankungen. Georg Thieme [3] Plotkin S, Orenstein W, Offit P. Vaccines. 6 ed: Saunders [7] Quast U, Stück B. Deutsches Grünes Kreuz (Ed.). Ärzte Merkblatt On the vaccinaton reactions: [1] Demicheli V, Rivetti A, Debalini MG et al. Vaccines for measles, mumps and rubella in children. Cochrane Database of Syst Rev 2012;2:CD [8] Black C, Kaye JA, Jick H. MMR vaccine and idiopathic thrombocytopaenic purpura. British Journal of Clinical Pharmacology 2003;55(1): [9] Patja A, Mäkinen-Kiljunen S, Davidkin I, et al. Allergic reactions to measles-mumps-rubella vaccination. Pediatrics

6 2001;107(2):e27. Actuality of the fact box Last update: April 2016 [10] Vestergaard M, Hviid A, Madsen KM et al. MMR vaccination and febrile seizures: evaluation of susceptible subgroups and longterm prognosis. JAMA 2004;292(3): [11] Wilson K, Hawken S, Kwong JC et al. Adverse events following 12 and 18 month vaccinations: a population-based, self-controlled case series analysis. PLoS One 2011;6(12):e27897.