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Meningitis

About Group B streptococcus Disease

About Haemophilus influenzae Serotype b (Hib) Disease

About Meningococcal Disease

About Streptococcus pneumoniae Disease


Group B streptococcus Disease

Group B streptococcus (GBS) is a type of bacterium that causes illness in newborn babies, pregnant women, the elderly, and adults with other illnesses, such as diabetes or liver disease. GBS is the most common cause of life-threatening infections in newborns.

How common is GBS disease?

GBS is the most common cause of sepsis (blood infection) and meningitis (infection of the fluid and lining surrounding the brain) in newborns.
GBS is a frequent cause of newborn pneumonia and is more common than other, better known, newborn problems such as rubella, congenital syphilis, and spina bifida. Before prevention methods were widely used, approximately 8,000 babies in the United States would get GBS disease each year. One of every 20 babies with GBS disease dies from infection. Babies that survive, particularly those who have meningitis, may have long-term problems, such as hearing or vision loss or learning disabilities. In pregnant women, GBS can cause bladder infections, womb infections (amnionitis, endometritis), and stillbirth. Among men and among women who are not pregnant, the most common diseases caused by GBS are blood infections, skin or soft tissue infections, and pneumonia.
Approximately 20% of men and nonpregnant women with GBS disease die of the disease.

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Does everyone who has GBS get sick?

Many people carry GBS in their bodies but do not become ill. These people are considered to be "carriers." Adults can carry GBS in the bowel, vagina, bladder, or throat. One of every four or five pregnant women carries GBS in the rectum or vagina. A fetus may come in contact with GBS before or during birth if the mother carries GBS in the rectum or vagina. People who carry GBS typically do so temporarily -- that is, they do not become lifelong carriers of the bacteria.

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How does GBS disease affect newborns?

Approximately one of every 100 to 200 babies whose mothers carry GBS develop signs and symptoms of GBS disease. Three-fourths of the cases of GBS disease among newborns occur in the first week of life ("early-onset disease"), and most of these cases are apparent a few hours after birth. Sepsis, pneumonia, and meningitis are the most common problems. Premature babies are more susceptible to GBS infection than full-term babies, but most (75%) babies who get GBS disease are full term. GBS disease may also develop in infants 1 week to several months after birth ("late-onset disease"). Meningitis is more common with late-onset GBS disease. Only about half of late-onset GBS disease among newborns comes from a mother who is a GBS carrier; the source of infection for others with late-onset GBS disease is unknown. Late-onset disease is very rare.

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How is GBS disease diagnosed and treated?

GBS disease is diagnosed when the bacterium is grown from cultures of sterile body fluids, such as blood or spinal fluid. Cultures take a few days to complete. GBS infections in both newborns and adults are usually treated with antibiotics (e.g., penicillin or ampicillin) given through a vein.

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Can pregnant women be checked for GBS?

GBS carriage can be detected during pregnancy by taking a swab of both the vagina and rectum for special culture. Physicians who culture for GBS carriage during prenatal visits should do so late in pregnancy (35-37 weeks’ gestation); cultures collected earlier do not accurately predict whether a mother will have GBS at delivery. A positive culture result means that the mother carries GBS -- not that she or her baby will definitely become ill. Women who carry GBS should not be given oral antibiotics before labor because antibiotic treatment at this time does not prevent GBS disease in newborns. An exception to this is when GBS is identified in urine during pregnancy. GBS in the urine should be treated at the time it is diagnosed. Carriage of GBS, in either the vagina or rectum, becomes important at the time of labor and delivery -- when antibiotics are effective in preventing the spread of GBS from mother to baby.

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Can GBS disease among newborns be prevented?

Most GBS disease in newborns can be prevented by giving certain pregnant women antibiotics through the vein during labor. Any pregnant woman who previously had a baby with GBS disease or who has a urinary tract infection caused by GBS should receive antibiotics during labor.
Pregnant women who carry GBS should be offered antibiotics at the time of labor or membrane rupture. GBS carriers at highest risk are those with any of the following conditions:

  • fever during labor
  • rupture of membranes (water breaking) 18 hours or more before delivery
  • labor or rupture of membranes before 37 weeks

Because women who carry GBS but do not develop any of these three complications have a relatively low risk of delivering an infant with GBS disease, the decision to take antibiotics during labor should balance risks and benefits. Penicillin is very effective at preventing GBS disease in the newborn and is generally safe. A GBS carrier with none of the conditions above has the following risks:

  • 1 in 200 chance of delivering a baby with GBS disease if antibiotics are not given
  • 1 in 4000 chance of delivering a baby with GBS disease if antibiotics are given
  • 1 in 10 chance, or lower, of experiencing a mild allergic reaction to penicillin (such as rash)
  • 1 in 10, 000 chance of developing a severe allergic reaction--anaphylaxis--to penicillin. Anaphylaxis requires emergency treatment and can be life-threatening.

If a prenatal culture for GBS was not done or the results are not available, physicians may give antibiotics to women with one or more of the risk conditions listed above.

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What research is being done on prevention of GBS disease?

In spite of testing and antibiotic treatment, some babies still get GBS disease. Vaccines to prevent GBS disease are being developed. In the future, women who are vaccinated may make antibodies that cross the placenta and protect the baby during birth and early infancy.

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Who is at higher risk for GBS disease?

Pregnant women with the following conditions are at higher risk of having a baby with GBS disease:

  • previous baby with GBS disease
  • urinary tract infection due to GBS
  • GBS carriage late in pregnancy
  • fever during labor
  • rupture of membranes 18 hours or more before delivery
  • labor or rupture of membranes before 37 weeks

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Haemophilus influenzae Serotype b (Hib) Disease

Clinical Features

Before the availability of the Haemophilus influenzae serotype b (Hib) conjugate vaccine in the United States and other industrialized countries, more than one-half of Hib cases presented as meningitis with fever, headache, and stiff neck. The remainder presented as cellulitis, arthritis, or sepsis. In developing countries, Hib is still a leading cause of bacterial pneumonia deaths in children.

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Etiologic Agent

Haemophilus influenzae serotype b.

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Incidence

During 1980-1990, incidence was 40-100/100,000 children < 5 years old in the United States. Due to routine use of the Hib conjugate vaccine since 1990, the incidence of invasive Hib disease has decreased to 1.3/100,000 children. However, Hib remains a major cause of lower respiratory tract infections in infants and children in developing countries where vaccine is not widely used.

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Sequelae

3%-6% of cases are fatal; up to 20% of surviving patients have permanent hearing loss or other long-term sequelae.

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Transmission

Direct contact with respiratory droplets from nasopharyngeal carrier or case patient.

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Risk Groups

Infants and young children, household contacts, and day-care classmates. Surveillance

National surveillance is conducted through NETSS. Active laboratory-based surveillance is conducted in Emerging Infections Program sites and other areas of the United States.

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Trends

Since licensure of conjugate vaccines for infants (1990) and children (1987), rates of disease among children <5 years old have declined by more than 95% in the United States, while rates for adults have remained stable. However, rates of disease among Alaskan natives remain higher than elsewhere in the United States.

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Challenges

Elimination of persistent Hib disease in the United States. Currently available conjugate vaccines differ in immuno-genicity in very young children and possibly in duration of antibody persistence, raising questions about long-term efficacy (>5 years), optimal use, and schedules. Monitoring the possible emergence of disease due to other serotypes. Problems with serotyping of H. influenzae in state health departments. Development of rapid molecular assays for detection and molecular subtyping of all Hi strains. The cost of Hib conjugate vaccines has limited their use in developing countries even though Hib is a major cause of morbidity and mortality.

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Opportunities

Evaluating the characteristics of Hib vaccines associated with prevention of carriage and invasive disease will facilitate application of this technology to development of conjugate vaccines for other organisms with polysaccharide capsules (such as the meningococcus, pneumococcus, and group B streptococcus). Further evaluation of herd immunity effects may lead to insight into vaccination strategies that optimize protection against invasive disease and transmission of Hib organisms.

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Meningococcal Disease

What is meningitis?

Meningitis is an infection of the fluid of a person's spinal cord and the fluid that surrounds the brain. People sometimes refer to it as spinal meningitis. Meningitis is usually caused by a viral or bacterial infection. Knowing whether meningitis is caused by a virus or bacterium is important because the severity of illness and the treatment differ. Viral meningitis is generally less severe and resolves without specific treatment, while bacterial meningitis can be quite severe and may result in brain damage, hearing loss, or learning disability. For bacterial meningitis, it is also important to know which type of bacteria is causing the meningitis because antibiotics can prevent some types from spreading and infecting other people. Before the 1990s, Haemophilus influenzae type b (Hib) was the leading cause of bacterial meningitis, but new vaccines being given to all children as part of their routine immunizations have reduced the occurrence of invasive disease due to H. influenzae. Today, Streptococcus pneumoniae and Neisseria meningitidis are the leading causes of bacterial meningitis.

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What are the signs and symptoms of meningitis?

High fever, headache, and stiff neck are common symptoms of meningitis in anyone over the age of 2 years. These symptoms can develop over several hours, or they may take 1 to 2 days. Other symptoms may include nausea, vomiting, discomfort looking into bright lights, confusion, and sleepiness. In newborns and small infants, the classic symptoms of fever, headache, and neck stiffness may be absent or difficult to detect, and the infant may only appear slow or inactive, or be irritable, have vomiting, or be feeding poorly. As the disease progresses, patients of any age may have seizures.

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How is meningitis diagnosed?

Early diagnosis and treatment are very important. If symptoms occur, the patient should see a doctor immediately. The diagnosis is usually made by growing bacteria from a sample of spinal fluid. The spinal fluid is obtained by performing a spinal tap, in which a needle is inserted into an area in the lower back where fluid in the spinal canal is readily accessible. Identification of the type of bacteria responsible is important for selection of correct antibiotics.

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Can meningitis be treated?

Bacterial meningitis can be treated with a number of effective antibiotics. It is important, however, that treatment be started early in the course of the disease. Appropriate antibiotic treatment of most common types of bacterial meningitis should reduce the risk of dying from meningitis to below 15%, although the risk is higher among the elderly.

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Is meningitis contagious?

Yes, some forms of bacterial meningitis are contagious. The bacteria are spread through the exchange of respiratory and throat secretions (i.e., coughing, kissing). Fortunately, none of the bacteria that cause meningitis are as contagious as things like the common cold or the flu, and they are not spread by casual contact or by simply breathing the air where a person with meningitis has been.However, sometimes the bacteria that cause meningitis have spread to other people who have had close or prolonged contact with a patient with meningitis caused by Neisseria meningitidis (also called meningococcal meningitis) or Hib. People in the same household or day-care center, or anyone with direct contact with a patient's oral secretions (such as a boyfriend or girlfriend) would be considered at increased risk of acquiring the infection. People who qualify as close contacts of a person with meningitis caused by N. meningitidis should receive antibiotics to prevent them from getting the disease. Antibiotics for contacts of a person with Hib meningitis disease are no longer recommended if all contacts 4 years of age or younger are fully vaccinated against Hib disease (see below).

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Are there vaccines against meningitis?

Yes, there are vaccines against Hib and against some strains of N. meningitidis and many types of Streptococcus pneumoniae. The vaccines against Hib are very safe and highly effective.

There is also a vaccine that protects against four strains of N. meningitidis, but it is not routinely used in the United States. The vaccine against N. meningitidis is sometimes used to control outbreaks of some types of meningococcal meningitis in the United States. Meningitis cases should be reported to state or local health departments to assure follow-up of close contacts and recognize outbreaks. College freshman, especially those who live in dormitories are at higher risk for meningococcal disease and should be educated about the availability of a safe and effective vaccine which can decrease their risk. Although large epidemics of meningococcal meningitis do not occur in the United States, some countries experience large, periodic epidemics. Overseas travelers should check to see if meningococcal vaccine is recommended for their destination. Travelers should receive the vaccine at least 1 week before departure, if possible. Information on areas for which meningococcal vaccine is recommended can be obtained by calling the Centers for Disease Control and Prevention at (404)-332-4565.There are vaccines to prevent meningitis due to S. pneumoniae (also called pneumococcal meningitis) which can also prevent other forms of infection due to S. pneumoniae. The pneumococcal polysaccharide vaccine is recommended for all persons over 65 years of age and younger persons at least 2 years old with certain chronic medical problems. There is a newly licensed vaccine (pneumococcal conjugate vaccine) that appears to be effective in infants for the prevention of pneumococcal infections and is routinely recommended for all children greater than 2 years of age.

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About Streptococcus pneumoniae Disease

Clinical Features

Pneumonia, bacteremia, otitis media, meningitis, sinusitis, peritonitis and arthritis.

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Etiologic Agent

Streptococcus pneumoniae. More than 90 serotypes exist; of strains causing invasive disease, 88% are serotypes included in the 23-valent polysaccharide vaccine. Before the new pneumococcal conjugate vaccine was introduced in 2001, over 80% of invasive isolates in children <5 years old were included in the 7-valent vaccine.

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Incidence

Until 2000, S. pneumoniae infections caused 100,000-135,000 hospitalizations for pneumonia, 6 million cases of otitis media, and 60,000 cases of invasive disease, including 3300 cases of meningitis. Incidence of sterile-site infections showed geographic variation from 21 to 33 cases per 100,000 population. Disease figures are now changing due to conjugate vaccine introduction.; in 2002, the rate of invasive disease was 13 cases per 100,000 in the United States.

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Sequelae

Death occurs in 14% of hospitalized adults with invasive disease. Neurologic sequelae and/or learning disabilities can occur in meningitis patients. Hearing impairment can result from recurrent otitis media.

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Transmission

Person to person.

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Risk Groups

Persons at higher risk for infection are the elderly, children under 2 years old, blacks, American Indians and Alaska Natives, children who attend group day care centers, and persons with underlying medical conditions including HIV infection and sickle-cell disease.

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Surveillance

Active, population-based surveillance is conducted in nine states (total population: 25 million). Reporting of drug-resistant S. pneumoniae and all invasive disease in children <5 years old has been mandated in several states. A nationwide system tracks invasive disease occurring in children <5 years who have been vaccinated.

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Trends

The incidence among young adults and young children is decreasing, due to improved HIV therapy and to use of the new conjugate vaccine for children. Outbreaks have occurred in institutional settings and child care centers. In the United States, ß-lactam resistance is common and prevalence of strains resistant to multiple classes of drugs is increasing.

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Challenges

Supplies of pneumococcal conjugate vaccine are inadequate. The 23-valent polysaccharide vaccine is underused. Sensitive, rapid diagnostic tests are not available for many types of pneumococcal infections, although a new urinary antigen test may be useful in adults. Widespread overuse of antibiotics contributes to emerging drug resistance.

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Opportunities

Ability to prevent infections could improve through expanded use of 23-valent polysaccharide vaccine among adults and through use of the conjugate vaccine for infants and young children. Campaigns for judicious use of antibiotics along with the new vaccine may slow or reverse emerging drug resistance.

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Meningitis