VACCINE-PREVENTABLE DISEASES

In document Immunization Handbook (Page 47-55)

Tuberculosis (Tb)

Description: Tuberculosis is caused by a bacterium, Mycobacterium tuberculosis. The most important route of spread is through inhalation of droplets of pulmonary secretions from a coughing infective person. Close contact is normally required for transmission and the source of infection is likely to be a person within the family when a child is

diagnosed with Tb. People of all ages can contract Tb but young children are more susceptible to infection and they are also at higher risk of developing severe disease, such as Tb meningitis (brain infection), Tb osteitis (bone infection) or disseminated Tb (infection in many different parts of the body). Adults with Tb infection will usually have a chronic cough but young children often have indistinctive symptoms such as tiredness and failure to thrive

Vaccine: The BCG vaccine (Bacillus Calmette Guerin) is made from an attenuated (=weakened) strain of Mycobacterium bovis and was first developed in the early 20th century. BCG is a live vaccine, which

vaccine will multiply in the body after immunization and create an immune response. Immunization with BCG protects children particularly against the severe forms of tuberculosis but it will not prevent all cases of tuberculosis in a population.

Diphtheria

Description: Diphtheria is caused by the toxin (toxin=poison) producing Corynebacterium diphteriae bacterium. Transmission is by personal contact through droplets produced by coughing and sneezing. Crowding, poverty and poor access to health care are important risk factors for diphtheria. The typical patient with diphtheria is below 15 years of age and not fully immunized. Symptoms are sore throat, loss of appetite and slight fever. The severity varies with the site of infection and many infections are unapparent resulting in asymptomatic patients carrying and transmitting the infection for long periods. The serious forms include infections in the throat and tonsils causing swelling that can block the airways. A typical membrane is formed in the throat. Diphtheria can also infect the skin causing painful, red swollen sores not unlike impetigo.

Vaccine: The Diphtheria vaccine is a toxoid, that is the inactivated toxin produced by the Corynebacterium. When the diphtheria toxin is treated with formaldehyde it loses its ability to bind to cells and will no longer cause disease. The inactivated toxin induces a strong immune response with production of antitoxin antibodies. The anti-toxin antibodies will protect from the diseases since the mortality from diphtheria is caused by the toxin.

Tetanus

Description: Tetanus is caused by another toxin (poison) producing bacteria, Clostridium tetani, that lives in soil. The toxin binds to nerve cells in the spinal cord and the brain making muscles contract

involuntary. The muscle spasms interfere with breathing and swallowing and mortality is very high. The site of infection is often a skin lesion. A newborn baby can become infected if the umbilical cord is cut with a contaminated

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instrument or infected material is used to dress the cord. This is called neonatal tetanus and symptoms appear three to ten days after birth. The first sign is that the baby is unable to suck because of muscle spasms in the throat and around the mouth. The spasms will increase and

eventually involve the entire body and few affected babies survive. Neonatal tetanus can be prevented if mothers are immunized against tetanus before or during pregnancy. Maternal antibodies against the tetanus toxin are then transported over the placenta to the baby during pregnancy and will protect the baby against tetanus until it has been immunized. After 20 years without tetanus, Pohnpei had two cases in 2003. A six-year-old child with no history of vaccination and a fatal case in newborn with a unvaccinated mother.

Vaccine: Tetanus vaccine is a toxoid, the inactivated form of the natural toxin produced by the tetanus bacteria. When the toxin is treated with formaldehyde it is no longer poisonous but it still induces an immune response. Anti-toxin antibodies protect from disease by inactivating the toxin produced by the bacteria. Like diphtheria, the disease tetanus is caused by the toxin produced by the bacteria.

Pertussis (WhoopinG cough)

Description: Whooping cough is caused by the Bordetella pertussis, bacteria that produce several different toxins. The infection is

particularly dangerous for infants because the intensive coughing can interfere with breathing and feeding. The illness starts with a runny nose, red eyes and low-grade fever. A cough develops over several days culminating with frequent episodes of intensive coughing. During severe attacks the face and hands of the baby may turn blue (cyanotic) due to lack of oxygen when the coughing interferes with breathing. Small blood vessels in the outer layer of the eye can break from the intensive coughing causing typical haemorrhages in the eye. Coughing and vomiting is exhaustive and the lack of oxygen can lead to brain damage in severe cases.

Vaccine: There are several different kinds of pertussis vaccine but they can be divided into two major groups, whole cell vaccines and acellular vaccines. Both types of vaccines are often combined with diphtheria and tetanus vaccine. The pertussis vaccine used in the FSM is of the whole cell/acellular type and comes in a combination with diphtheria and tetanus vaccines called DPT.

Hepatitis B

Description: Hepatitis B virus (HBV) spreads from person to person through body fluids and sexual contact without condom is an important route of infection. The virus can also spread from mother to child during delivery and breastfeeding. Hepatitis B virus can cause liver cirrhosis and liver cancer many years after the initial infection and infection with hepatitis B virus is the most important cause of liver cancer in the world. Infection with hepatitis B is common in the FSM and around 12% of the people tested for blood donation are positive for the infection. Hepatitis B immunization of newborns started in 1988. Vaccine: The vaccine used in the FSM is a recombinant DNA vaccine. Children are infected early in life and most transmission is from mother to child during and soon after delivery. It is therefore very important that the Hepatitis B vaccine is given as soon as possible after birth and every effort should be made to immunize all newborns within 12 hours. Infants born to mothers who are HbsAg-positive (Hepatitis B Carriers) are at extremely high risk of HVB transmission and chronic HBV infection. Hepatitis B Immune Globulin is provide to the exposed child within 12 hours of birth.

Measles

Description: Measles is caused by a virus that spreads easily via airborne droplets and through direct contact. Measles is most infectious during the 10-12 days incubation period when the infected person does not yet have symptoms. The first signs are high fever together with cough, runny nose, and red eyes. Small

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white spots on the inside the cheeks called Koplik’s spots are typical for measles but they are not always seen. A rash consisting of small, elevated papules on red skin (maculo-papular rash), sometimes with a haemorrhagic centre, appears 2-4 days after the onset of fever. It starts on the head and spreads to the trunk and extremities. The rash fades in the same order it appeared, often with scaling of the skin. The infection can be complicated with pneumonia and diarrhoea and children with malnutrition are especially at risk of death. One of the goals of the EPI is to eradicate measles from the world. To do that it is very

important to report and investigate all cases of fever with rash to establish whether or not it is measles. If you come across a child with fever and rash, you should refer the child to the nearest hospital for testing.

Vaccine: Measles vaccine is a weakened (attenuated) live virus. Reconstituted measles vaccine is sensitive to heat. Maternal antibodies can interfere with the development of immunity and it is therefore important not to give the measles vaccine too early in life. At the same time you do not want to wait too long because it increases the risk that the child is infected with measles. Measles vaccine is often combined with vaccines against rubella and mumps. A combined

measles/mumps/ rubella vaccine (MMR vaccine) is used in the Federated States of Micronesia and it is given at 12 months of age with a second dose one month later. The last outbreak of measles in the FSM occurred in Chuuk in 1994 and killed 13 children.

Rubella

Rubella is a virus that is spread with respiratory droplets through the air. The illness is usually mild with low-grade fever and a rash that can be mistaken for measles rash. Other symptoms include swollen lymph nodes, tiredness and red eyes. The most serious consequences of rubella result from infection before birth. If a pregnant woman is infected with rubella, the virus will infect also the unborn child. There is a very high risk, especially if the infection occurred during the first three months of pregnancy, that the child could be born with

complications such as undeveloped brain, heart malformation, blindness and deafness.

This is the main reason why we immunize against this otherwise mild disease.

Vaccine: Rubella vaccine is usually given in a combination with measles as MMR vaccine

Mumps

Mumps is an acute viral disease characterized by fever, swelling and tenderness of one or more salivary glands. Orchitis (infection of testis), usually unilateral, occurs in 20-30% of postpubertal males. Sterility is an extremely rare consequence of mumps. This disease often involves the central nervous system usually as aseptic meningitis, and may result in deafness.

Vaccine: Mumps vaccine is combined with measles and rubella as MMR.

Haemophilus influenza Type b:

This is one of the most common bacterial meningitis in children 2 months to five years. It is usually associated with bacteraemia. The onset can be subacute or (usually) sudden; symptoms are those of fever, vomiting, lethargy and meningeal irritation, with bulging fontanelle in infants or stiff neck and back in older children. The case fatality rate for Hib meningitis is about 5% and up to 40% of the survivors had neurological sequelae such as deafness and intellectual impairment. Vaccine: The FSM immunization program commonly uses PedvaxHIB. This 3 dose series begins at 2 months of age, 4 months and a booster at 12 months. However, all 3 conjugate Hib vaccines licensed for use in infants are interchangeable. Children starting late with Hib immunization may not require a full series of 3 (or four) doses. Unvaccinated children aged 2-12 months should receive two doses of vaccine, 2 months apart followed by a booster at 12-15 months of age, at least two months after the last dose. Unvaccinated children aged 12-14 months should receive two doses of the vaccine, 2 months apart.

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Any previously unvaccinated child 15 -59 months of age should receive a single dose of vaccine.

Pneumococcal Disease

This disease is caused by streptoccus pneumoniae results in widespread illness and death throughout the world each year. Transmission occurs as a result of direct person-to-person contact via droplets. The spread of the organism within a family or household is influenced by such factors as crowding. The major clinical syndromes of this illness include pneumonia, bacteremia and meningitis.

Pneumococcal pneumonia is the most common clinical presentation of pneumococcal disease in adults. Symptoms generally include an abrupt onset of fever and shaking chills and rigor. Other common symptoms include chest pains, cough with rusty sputum, and shortness of breath, rapid breathing, rapid heart rate, malaise and weakness.

Pneumococcal bacteremia occurs in about 25%-30% of patients with pneumococcal pneumonia. Rates are higher in the very young and the elderly. The over all mortality for bacteremia is about 20%, but may be as high as 60% in elderly patients

Pneumococcal meningitis has a very high fatality rate of 30%, but may be as high as 80% in elderly patients. Neurological sequelae are common among survivors.

Vaccine: Two pneumococcal vaccines are currently available in the FSM. Pneumovax23 produced by Merck Sharpe & Dohme is available in the FSM and targeted to the elderly and people with chronic illness. A single dose is given to everyone over the age of 50 years and to anyone over the age of two years with normal immune systems who have chronic illness, including heart disease, lung disease, diabetes, alcoholism, cirrhosis

Pneumococcal conjugate vaccine.7 valent “Prevenar” is now available in the FSM. The National Immunization Program introduced this vaccine in 2008. The routine schedule is 4 doses, one dose at each at: 2 months, 4 months, 6 months and 12-15 months.

Influenza

Influenza or the flu is a highly infectious viral disease with fever, headache, muscle ache, prostration, runny nose, sore throat and cough. The mode of transmission is by infected airborne droplets spread person-to-person. Outbreaks of flu can develop very rapidly and may quickly result in many deaths. The very young and the very old are at the highest risk of death. In the FSM there is no “Flu season” as found in USA and Australia. The flu is found all year long.

Vaccine: Influenza vaccine normally contains 3 strains of virus, two current influenza A subtypes and influenza B, representing currently circulating subtypes. The Flu vaccine is changed every year to protect against the types of flu virus presently infecting people. Therefore a flu shot is required every year because the vaccine changes each year. A single dose is given once a year to everyone over the age of 50 years. Also to everyone regardless of age, who have chronic illness, including heart disease, lung disease, diabetes, alcoholism, smokers and cirrhosis. In children 6 months to 9 years of age receiving influenza vaccine for the first time, should receive two doses administered at least a month apart. Pregnant women are considered high risk and should be vaccinated.

While the immunization program targets the high-risk

populations, the influenza vaccine may be taken by anyone who wishes to be protected against influenza.

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In document Immunization Handbook (Page 47-55)