American Academy of Pediatrics. Committee on Infectious Diseases. Policy statement: recommendations for the prevention of pneumococcal infections, including the use of pneumococcal conjugate vaccine (Prevnar), pneumococcal polysaccharide vaccine, and antibiotic prophylaxis.
Heptavalent pneumococcal conjugate vaccine (PCV7) is recommended for universal use in children 23 months and younger, to be given concurrently with other recommended childhood vaccines at 2, 4, 6, and 12 to 15 months of age. For children 7 to 23 months old who have not received previous doses of PCV7, administration of a reduced number of doses is recommended. Two doses of PCV7 are recommended for children 24 to 59 months old at high risk of invasive pneumococcal infection-including children with functional, anatomic, or congenital asplenia; infection with human immunodeficiency virus; and other predisposing conditions-who have not been immunized previously with PCV7. Recommendations have been made for use of 23-valent pneumococcal polysaccharide (23PS) vaccine in high-risk children to expand serotype coverage. High-risk children should be given vaccines at the earliest possible opportunity. Use of antibiotic prophylaxis in children younger than 5 years with functional or anatomic asplenia, including children with sickle cell disease, continues to be recommended. Children who have not experienced invasive pneumococcal infection and have received recommended pneumococcal immunizations may discontinue prophylaxis after 5 years of age. The safety and efficacy of PCV7 and 23PS in children 24 months or older at moderate or lower risk of invasive pneumococcal infection remain under investigation. Current US Food and Drug Administration indications are for administration of PCV7 only to children younger than 24 months. Data are insufficient to recommend routine administration of PCV7 for children at moderate risk of pneumococcal invasive infection, including all children 24 to 35 months old, children 36 to 59 months old who attend out-of-home care, and children 36 to 59 months old who are of Native American (American Indian and Alaska Native) or African American descent. However, all children 24 to 59 months old, regardless of whether they are at low or moderate risk, may benefit from the administration of pneumococcal immunizations. Therefore, a single dose of PCV7 or 23PS vaccine may be given to children 24 months or older. The 23PS is an acceptable alternative to PCV7, although an enhanced immune response and probable reduction of nasopharyngeal carriage favor the use of PCV7 whenever possible.
To assess effectiveness of Act-HIB vaccine forprevention of acute respiratory diseases.
Nine hundred immunized children 1 - 5 years old as well as not immunized children of the same age were followed-up. Criteria for clinical effectiveness of the vaccine were rate of acute respiratory infection episodes, duration of disease episode, and rate of complications development. Level of nasopharyngeal coverage were also studied by bacteriological tests of nasopharyngeal secretion samples.
Obtained data showed that immunization leads to increase of host's resistance capabilities, decrease of acute respiratory disease incidence and changes in structure of complications due to infection.
Prevention of Hib-infection using Act-HIB vaccine leads to decrease of acute respiratory disease rates and severity of infections. Total incidence of acute respiratory infections in children aged 1 - 5 years decreased by 27%, whereas incidence of pneumonia, bronchitis, and sinusitis - by 50%. Vaccination resulted in decrease of antibiotic use, number of pediatric consultations.
To compare two Haemophilus influenzae type B (HiB) conjugate vaccines, a polysaccharide-diphtheria toxoid conjugate (PRP-D) vaccine and an oligosaccharide-CRM197 protein conjugate (HBOC [PRP-CRM]) vaccine, in the same population.
One hundred twenty-five thousand infants were randomized to receive the PRP-D or HBOC vaccine. Primary immunization consisted of two doses of either vaccine administered at 4 and 6 months and a booster dose was given at 14 to 18 months. Protection was assessed by recording episodes of invasive disease with HiB isolated from the blood or another normally sterile body site.
One thousand thirty-six child health care centers in Finland.
Infants born in Finland during the 24-month period from 1987 to 1989.
Each vaccine dose was injected intramuscularly in a volume of 0.5 mL. At the same time, a separate site was injected with the diphtheria and tetanus toxoids and pertussis vaccine at 4 months of age, with inactivated poliovirus vaccine at 6 months of age, and with measles-mumps-rubella vaccine at 14 to 18 months of age.
The mean anticapsular antibody concentration 1 month after the second dose was 0.63 micrograms/mL and 4.32 micrograms/mL in the PRP-D and HBOC vaccine recipients, respectively. The booster dose resulted in a high antibody concentration: 33.3 micrograms/mL and 58.3 micrograms/mL for PRP-D and HBOC vaccine recipients, respectively. At 36 months of age, the antibody concentration declined to 2.5 micrograms/mL and 5.6 micrograms/mL for PRP-D and HBOC vaccine recipients, respectively. After two doses of the vaccine, there were five episodes (39 were expected based on historical controls) of invasive HiB disease in the PRP-D group and two episodes (35 were expected) in the HBOC group. Hence, an 87% (95% confidence limit [CL], 69, 96) protection rate in the PRP-D group and a 95% (95% CL, 76, 99) protection rate in the HBOC group were achieved. No episodes occurred after the booster dose in either group.
Both the PRP-D and HBOC vaccines are safe and effective. A two-dose primary vaccination schedule seems appropriate, at least in circumstances prevailing in Finland and probably in other areas with similar epidemiological effects of HiB disease.
Prior to the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines, Hib was the leading cause of bacterial meningitis in children under five years of age worldwide. In countries that have adopted Hib vaccination schedules, invasive disease has reduced markedly. Oro-naso pharyngeal carriage is recognized as the most significant source of infection. Hib carriage is significantly associated with poverty, such as overcrowding, poor ventilation in houses, lack of running water, and high smoking rates. Additionally, many Indigenous minority groups report high rates of Hib carriage. A resurgence of Hib disease among Alaskan children in the 1990s, lead to a change in approach to eliminate Hib disease and carriage in high-risk populations. This new approach identifies strategies for eliminating Hib disease focusing on the reservoirs of colonization within families and communities. Monitoring Hib carriage continues to offer an early warning system, whereby intervention could prevent invasive disease resurgence.
Do we need a booster of Hib vaccine after primary vaccination? A study on anti-Hib seroprevalence in Sweden 5 and 15 years after the introduction of universal Hib vaccination related to notifications of invasive disease.
The prevalence of IgG ELISA antibodies against Haemophilus influenzae polyribosyl ribitol phosphate (anti-Hib) was studied in two Swedish seroepidemiologic materials. One study was performed in 1997 5 years after the introduction of universal Hib vaccination (N=3320). Ten years later, a similar study was carried out to analyze the effect of vaccination on anti-Hib prevalence (N=2383). The median values of anti-Hib concentrations (EU/mL) were almost identical in the two materials. The antigenic pressure including vaccination, natural infections and possible cross-immunizations was thus assumed to be constant. The joint median was 0.50 EU/mL (95% confidence interval: 0.46, 0.56). However, there were also indications of reduced exposure to 'Hib-antigens' over a 10-year period. The proportion above the cut-off point for protection, 0.15 EU/mL, decreased significantly for children aged 2-19 years from 78% in 1997 to 74% in 2007 (p=0.034), and there was a significant increase in values below the minimal level of detection for adults from 17% in 1997 to 20% in 2007 (p=0.009). In the 2007 material no specific age group could be identified with a lower immune profile than other age groups older than 3 years and there was a significant downward trend of invasive infections caused by Hib according to notification data for the period 1997-2008. Therefore, the conclusion is that presently there is no need for a booster dose of Hib vaccine in Sweden after primary vaccination but the situation should be carefully monitored.
Immunization with a tetanus-protein (TT) pneumococcal polysaccharide (PPS) conjugate vaccine (Pnc1-TT) induces protective immunity against lethal pneumococcal infections in neonatal and infant mice, but anti-PPS IgG response and protective efficacy is lower than in adult mice. Here, we show that reduced antibody (Ab) response and protection against infections is directly related to impaired T cell response to the carrier. Whereas spleen cells from adult mice immunized with Pnc1-TT responded with proliferation and IFN-gamma secretion to in vitro stimulation with TT, spleen cells from neonatal and infant mice did not. However, significant, but age dependent, Th2-cytokine responses were observed in mice immunized with Pnc1-TT. Impaired IFN-gamma production upon TT-stimulation in vitro was also reflected in reduced IFN-gamma/IL-5 ratio. The IL--5 response correlated with IgG anti-PPS titers, and the lack of PPS Ab in the majority of neonatal mice was clearly associated with absence of carrier-specific IL-5 production. These results show that immunization with Pnc1-TT induces carrier-specific T cell responses that increase with age and determine the levels of PPS-specific Ab elicited. Whereas a weak and Th2-biased response was observed in neonatal mice, infant mice showed a mixed Th1-Th2 response as observed in adults.
In the province of Quebec, Canada, pneumococcal conjugate vaccine (PCV) is offered to all children aged less than 5 years, and a 2+1 schedule (2, 4, and 12 months) is recommended for low-risk infants, with other schedules including a lower number of doses for older children.
To estimate PCV effectiveness against invasive pneumococcal disease (IPD).
IPD cases in children aged 2-59 months and reported during the years 2005-2007 were eligible and uninfected controls were randomly identified in the provincial health insurance registry. Parents were interviewed by telephone and immunization records were reviewed. The PCV effectiveness was computed using unconditional logistic regression models adjusting for potential confounders.
180 IPD cases (60.4% of total reported) and 897 controls were included. Predictors of IPD risk were age, season, high-risk medical conditions, day-care attendance, and low family income. Overall PCV protection (> or =1 dose) against IPD caused by any serotype was 60% (95% CI: 38%-75%), and was 92% (83%-96%) against IPD caused by vaccine serotypes. Among low-risk children who received the recommended 2+1 schedule, 6 cases of vaccine failure occurred after the first dose, 1 case after the second dose, and no cases after the booster dose.
These results confirm the effectiveness of PCV after 2 and 3 doses.
Haemophilus influenzae type b (Hib) was the major cause of invasive bacterial disease in the United States and Canada before the introduction of Hib conjugate vaccines. Between 10000 and 20000 cases of Hib meningitis and other serious diseases occurred each year, leading to death in at least 3% of all patients and long term neurologic problems in up to 25% of survivors of meningitis. Introduction of Hib conjugate vaccines in Canada and the United States, first in children 18 months and older and later as a routine infant immunization, dramatically decreased the incidence of disease. By 1995 Hib disease levels had declined by more than 95% below preimmunization levels. The remarkably rapid reduction in disease incidence was partly because of the ability of the vaccine to reduce nasopharyngeal carriage of the organism, leading, when given widely, to reduced rates of exposure and infection even in those not immunized. Complete elimination of Hib disease in North America, however, will require achievement of relatively high coverage rates, especially in hard to reach populations where much of the remaining disease is occurring.
Epidemiology of pertussis and Haemophilus influenzae type b disease in Canada with exclusive use of a diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae type b pediatric combination vaccine and an adolescent-adult tetanus-diphtheria-acellular pertussis vaccine: implications for disease prevention in the United States.
During the decade 1998-2007, a combination DTaP(5)-IPV/Hib vaccine was used exclusively in Canada to immunize infants and young children against diphtheria, tetanus, pertussis, polio, and invasive Haemophilus influenzae type b (Hib) disease.
Medline was used to search for publications during 1996-2008 related to the epidemiology and vaccine prevention of pertussis and invasive Hib disease in Canada. Related abstracts and presentations were reviewed, when available, and epidemiologic data since 1985 were obtained from the Public Health Agency of Canada public Web site.
Reports of pertussis have declined substantially in preschool and school-aged children during the past decade, and cyclical peaks in disease incidence have been blunted or eliminated. In provinces and territories where Tdap(5) vaccine has been administered to 14- to 16-year-olds, marked reductions of pertussis have been documented in adolescents as well as younger age groups, possibly due to herd immunity. Incidence rates of invasive Hib disease among Canadian children
To assess antibody titers afforded by meningococcal C- (MenC) tetanus toxoid conjugate vaccine at 12 months of age in three different immunization schedules.
This prospective study included three similar cohorts of healthy infants from 1-dose, 2-dose and 3-dose MenC infant immunization programs. Infants were enrolled at 12 months of age and given the final scheduled dose of MenC-tetanus toxoid conjugate vaccine with sera collected prior to and 1 month after the vaccination. Serum bactericidal activity (SBA) titers = 1:8 were considered protective.
Before the 12 month dose, participants had significantly different protective titers according to the number of prior doses received: 100% (95% CI 97.6-100%) of infants who had 2 prior doses (at 2 and 4 months) were protected compared to 84.0% (76.7-89.3%) of participants with one dose (at 2 months) and 27.6% (21.0-35.4%) of unvaccinated infants. All subjects were protected after the 12 month MenC dose, but titers were higher with prior priming.
Two MenC doses given in infancy afford optimal protection during the first year of life; however, substantial protection was seen after one dose at 2 months.