Reduced Dosage for Pneumococcal Vaccine in Infants Effect, Says Study

Infants who received two or three primary doses of the 7-valent pneumococcal conjugate vaccine (PCV-7) both had a decreased rate of carrying pneumococcal microorganisms that can cause pneumonia and other infections, compared to infants who were not vaccinated, according to a study in the July 8 issue of JAMA.

Crowded infant vaccine schedules and less favorable cost-effectiveness calculations have prompted exploration of reduced-dose vaccine schedules other than the currently recommended 3 + 1-dose schedule of PCV-7, which consists of 3 primary doses before age 6 months followed up by a booster vaccination in the second year of life, according to background information in the article. Difficulty in implementing the 3 + 1-dose schedule in developing countries is another reason for exploring reduced schedules. The effects of reduced-dose schedules of PCV-7 on pneumococcal carriage in children are largely unknown.

Elske J. M. van Gils, M.D., of the University Medical Center Utrecht, the Netherlands, and colleagues examined the effects of a 2-dose and 2 + 1-dose PCV-7 schedule on nasopharyngeal (upper part of the throat behind the nose) pneumococcal carriage in young children. The randomized trial included 1,003 healthy newborns and 1 of their parents in a general community in the Netherlands, with follow-up to age 24 months. Infants were randomly assigned to receive 2 doses of PCV-7 at 2 and 4 months; 2 + 1 doses of PCV-7 at 2, 4, and 11 months; or no dosage (control group).

No significant differences in vaccine serotype (a strain of microorganisms having a set of antigens in common), nonvaccine serotype, and overall pneumococcal carriage were observed at 6 months in both vaccine groups compared with the control group. At 12 months, vaccine serotype carriage rates were significantly lower in both vaccine groups compared with the control group, with 25 percent in the 2-dose schedule group, 20 percent in the 2 + 1-dose schedule group, and 38 percent in the control group. A further decrease of vaccine serotype carriage was found at 18 months after 2 + 1-dose schedule and at 24 months after 2 primary doses compared with the control group.

In analysis comparing the 2-dose and 2 + 1-dose schedules, the researchers observed a significant difference in vaccine serotype carriage at 18 months with 24 percent vaccine serotype carriage in the 2-dose schedule group compared with 16 percent in the 2 + 1-dose schedule group. At 24 months, the estimates for vaccine serotype carriage in both vaccine groups were at the same level with 15 percent in the 2-dose schedule group and 14 percent in the 2 + 1-dose schedule group, compared with 36 percent in the control group.

“In conclusion, both 2-dose and 2 + 1-dose schedules of PCV-7 significantly reduce vaccine serotype pneumococcal carriage in children. This study supports future implementation of reduced-dose PCV-7 schedules,” the authors write.

Source: JAMA. 2009;302[2]:159-167

Comments

  1. quiact says

    Pneumonia Thoughts

    Pneumonia is an inflammation and consolidation of lung tissue to due to an infectious agent, such as a bacteria, or virus. Most pneumonia cases are usually acquired in a community setting .

    Bacterial pneumonia occurs more often due to bacteria called S. Pneumo. About half of all people infected with this bacteria show no overt symptoms.

    Also, in comparison with viral pneumonia, bacterial pneumonia has a shorter duration and is also more severe in the damage the bacteria can do to the patient. If left untreated, pneumonia can lead to the critical diseases of meningitis or sepsis, if not death. In fact, pneumonia was the number one cause of death in the United States before the advent of antibiotics.

    Approximately 2 million, if not more, people acquire pneumonia every year. 40 to 60 thousand people die due to pneumonia every year, and pneumonia is the most common infectious cause of death that exists. More men get pneumonia than women.

    About 20 percent of CAP cases are viral rather than bacterial. So most of the time, an antibiotic will be needed for the pneumonia patient. Also, about 10 million doctor visits are due to CAP and the symptoms from the disease.

    Pneumonia acquired while a patient is in a medical institution for another medical reason is called nosocomial pneumonia. Often, the symptoms are more severe, as the patient usually has another serious medical issue that is being treated in the medical facility as they acquire this type of pneumonia.

    If this type of pneumonia is acquired at such a location, it usually happens after the first 48 hours of a patient being in such a facility. Also, the microbe that causes nosocomial pneumonia is usually S. Aureus, according to others.

    However, frequently the cause of pneumonia is by resistant bacteria that are difficult to kill, as they are shielded from adaptation, these bacteria, from the many existing antibiotics historically used as therapy for patients invaded by bacteria. Such bacteria, as MRSA or VRE, are most resistant to most antibiotics.
    Treatment for nosocomial pneumonia usually requires a longer period to restore the health of a patient with this diagnosis. About 25 percent of ICU patients without pneumonia acquire nosocomial pneumonia while there for another medical issue.

    Symptoms for the typical pneumonia patient may be a fever, a high heart rate, a productive cough, and inflamed lungs noted on an X-ray. A sputum sample is usually obtained from the suspected patient in order to determine what is causing the pneumonia.

    If it is bacterial, antibiotic therapy is initiated for a certain length of time to cure the infection. At the same time, the health care provider should rule out lung cancer or tuberculosis as the provider is assessing the patient. Chest X-Rays usually are taken to rule out such diseases.

    Patients who are suspected or are diagnosed with community acquired pneumonia (CAP) are often started an antibiotic regimen from what is called the macrolide class of antibiotics. Macrolides have been proven to shorten the length of time the disease exists in the patient who has pneumonia.

    How serious CAP is with a patient can be determined by what is called a risk stratification point system- which lists various symptoms and conditions that may be present in the suspected patient who may have pneumonia.

    Points are assigned to these symptoms, and the severity of them regarding the disease of pneumonia. If the point number exceeds 90 points, the pneumonia patient is admitted to a hospital for more aggressive treatment and evaluation. About a third of all patients with community acquired pneumonia require hospitalization.

    Elderly patients usually experience this type of severity with their CAP illness, as well as those people with compromised immune systems for whatever reason. Also, primary care physicians diagnose and treat typical pneumonia in the United States. In the United States, about 2 million or more people acquire pneumonia, and over 4 thousand people die from this disease every year.

    Worldwide, about 2 million children less than 5 years of age die every year due to pneumonia. Two pneumonia vaccinations are available presently. It has recently been proven that the polysaccharide pneumonia vaccine is not useful in preventing pneumonia. However, the conjugate pneumonia vaccine has been shown to prevent the disease, according to recent studies.

    The effective vaccine has experienced greater worldwide access recently to prevent what may be a very deadly disease without prevention and treatment, as it is believed to protect well over 50 percent of people who receive this vaccination from pneumonia.

    http://www.lungusa.org

    Dan Abshear

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