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A Practical Guide to Immunisation People who develop chronic infection are at increased risk of developing chronic hepatitis, cirrhosis and liver cancer. Premature death from chronic liver disease occurs in 15-25% of chronically infected people. Vaccine schedule in Ireland Prior to 2007, immunisation was recommended for high risk groups including healthcare workers, those with chronic hepatitis and spouses, sexual partners, family and household contacts of acute cases and carriers of hepatitis B virus. In 2007, following a review of the epidemiology of hepatitis B infection in Ireland by the National Immunisation Advisory Committee (NIAC) and supported by a pharmacoeconomical evaluation, hepatitis B vaccination was recommended as part of the primary childhood immunisation programme. The vaccine is administered at 2, 4 and 6 months with diphtheria, tetanus, whooping cough (pertussis), Hib and IPV vaccines (referred to as the “6-in-1” vaccine). Vaccination will also continue for those high-risk groups as outlined by NIAC. 4.2.4 Measles Epidemiology of disease and impact of vaccination Measles is an extremely infectious viral illness caused by the Morbillivirus. Measles occurs most commonly in the non-immunised 1-4 year old age group. 16000 14000 Mea s les Va ccine, 1985 Number of Notifications 12000 10000 MMR 1,1988 8000 MMR 2,1992 6000 4000 MR , 1995 2000 2006 2004 2002 2000 1998 1996 1994 1992 1990 1988 1986 1984 1982 1980 1978 1976 1974 1972 1970 1968 1966 1964 1962 1960 1958 1956 1954 1952 1950 1948 0 Year Figure 4.4: Measles cases reported in Ireland 1948-2006 Source: Health Protection Surveillance Centre Measles has been notifiable in Ireland since 1948 (Figure 4.4). The highest number of cases was recorded in 1959 when 15,124 cases were notified. In 1985 the measles vaccine was introduced into the Irish immunisation schedule. The number of reported cases in the immediate subsequent years dropped significantly, so that by 1991 just 135 cases were reported. However, a number of major outbreaks have occurred despite the routine immunisation programme. Page 32 Chapter 4: Vaccine Preventable Diseases A Practical Guide to Immunisation Clinical features The first stage of measles includes irritability, runny nose, conjunctivitis (red eyes), hacking cough and fever. These symptoms may last up to eight days. The typical measles rash starts from day four, beginning at the hairline and progressing downwards over the face, neck and body. The rash consists of flat red or brown blotches, which can flow into each other and lasts 4-7 days. Small white spots are also found inside the cheeks (Koplik’s spots). The patient may also experience diarrhoea, vomiting and abdominal pain. Photo courtesy of CDC The combined Measles, Mumps and Rubella (MMR) vaccine was introduced in 1988 and a second dose MMR was introduced in 1992 at 10-14 years. Following an outbreak in 1993 (4,328 cases) a Measles-Rubella (MR) campaign was introduced in 1995 and in 1999 the age group for the second dose of MMR was lowered to 4-5 years. However, concerns about vaccine safety kept uptake levels below the 95% uptake rate required for herd immunity, resulting in further outbreaks in 2000 and 2003. In 2000, 1603 cases occurred in Ireland. There were three deaths in children - two children died of pneumonia complicating measles and one child later died from post measles encephalitis. Transmission Measles is one of the most highly infectious communicable diseases. Measles is transmitted by airborne droplet spread e.g. when the infected person coughs or sneezes, or through direct contact with nasal or throat secretions of an infected patient. Incubation period The incubation period is generally about ten days but can range from 7-21 days. Period of infectivity A patient is infectious from beginning of first symptoms (usually about four days before onset of rash) to four days after appearance of the rash. Measles complications occur in approximately 30% of reported cases. It is estimated that one in 100 infected require hospital admission. Complications are generally more common in babies, older children, adults and the immunocompromised. Complications include Ear infection Pneumonia /Bronchitis Convulsion Diarrhoea Meningitis/encephalitis Late onset SSPE (progressive irreversible brain degeneration) Death Chapter 4: Vaccine Preventable Diseases (affects (affects (affects (affects (affects (affects 1 1 1 1 1 1 in in in in in in 20) 25) 200) 6) 1000) 8,000 children under 2 years) (affects 1 in 2,000) Page 33 A Practical Guide to Immunisation Vaccine schedule in Ireland Measles immunisation with the combined MMR vaccine is recommended for all children at 12 months as part of the primary childhood immunisation programme. A booster dose of MMR vaccine is recommended at 4-5 years. Single vaccines are not recommended. Measles and Autism In 1998, a study of autistic children raised the question of a connection between MMR vaccine and autism. This study has a number of limitations and involved only 12 children. In 2004, 10 of the 13 authors of the 1998 study retracted the conclusions of the study and stated that the data was not able to establish a causal link between MMR vaccine and autism. Since then several larger studies have found no relationship between MMR vaccine and autism. Measles Elimination The World Health Organisation European Region has prepared a strategic plan (2005-2010) to eliminate measles and rubella and prevent congenital rubella by 2010. The strategy includes ensuring that all children will have the opportunity to receive two doses of MMR vaccine. 4.2.5 Meningococcal disease Epidemiology of disease and impact of vaccination Meningococcal disease is caused by the bacterium Neisseria meningitidis of which there are several subtypes (A, B, C, Y, W135, X). Invasive meningococcal disease (meningitis or septicaemia) may occur at any age but is most common in infancy and early childhood with an additional smaller peak of disease activity in adolescents and young adults. In temperate climates such as Ireland the infection typically shows a seasonal variation with the majority of cases occurring in winter and early spring. Meningococcal vaccines have been available since the 1970s. However, the original polysaccharide vaccines did not provide long-term protection and were not effective in children under 24 months. New meningococcal C conjugate vaccines have been developed from purified capsular polysaccharides and are effective under 18 months of age and provide longer immunity. Prior to introduction of meningococcal C vaccine into the Irish Immunisation Schedule in 2000, serotype B and C infections were common in Ireland. The introduction of meningococcal C vaccine has led to a reduction in the number of cases of meningococcal disease and in deaths due to meningococcal disease (Figure 4.5). Other serotypes are more common in some parts of the world e.g. Group A in sub-Saharan Africa and W135 in Saudi Arabia. Transmission Transmission occurs through frequent and prolonged contact with respiratory secretions of a carrier from coughing, sneezing, and mouth-kissing. Depending on the age group, up to 1 in 10 people may carry these bacteria. Carriage is uncommon in infancy and early childhood but increases with age. Peak carriage rates may occur in the 15-19 year old group of whom 25% may be carriers. Carriage is typically followed by the development of immunity. Incubation period The incubation period ranges between 2-10 days. Period of infectivity Individuals are infectious as long as meningococcal bacteria are present in the nose and mouth. Page 34 Chapter 4: Vaccine Preventable Diseases