New combination vaccines

Synchrony in serum antibody response to conserved proteins of Moraxella catarrhalis in young children

Conserved Moraxella catarrhalis (Mcat) proteins, oligopeptide permease (Opp)A, hemagglutinin (Hag), outer membrane protein (OMP) CD, Pilin A clade 2 (PilA2), and Moraxella surface protein (Msp) 22 have been studied as vaccine candidates. Children who experience frequent acute otitis media (AOM) confirmed with pathogen identification by tympanocentesis are referred to as stringently-defined otitis prone (sOP). Synchrony of serum antibody responses against 5 Mcat proteins, OppA, Hag, OMP CD, PilA2, and Msp22 resulting from nasopharyngeal colonization and AOM was studied for 85 non-otitis prone (NOP) children and 34 sOP children. Changes in serum IgG were quantitated with ELISA. Serum IgG antibody levels against OppA, Hag, OMP CD, and Msp22 rose in synchrony in NOP and sOP children; that is, the proteins appeared equally and highly immunogenic in children at age 6 to 22-25 months old and then leveled off in their rise at 22-25 to 30 months old. In contrast, rises of PilA2 were slow from 6 months old and kept constant and did not level off significantly before 30 months old. OppA, Hag, OMP CD, and Msp22 elicited a synchronous acquisition of naturally-induced serum antibody in young children. A multi-valent Mcat protein vaccine combining OppA, Hag, OMP CD, and Msp22 may exhibit less antigen competition when administered as a combination vaccine in young children.

Mothers' preferences regarding new combination vaccines for their children in Japan, 2014

A number of new vaccines to prevent childhood diseases have been introduced globally over the last few decades. Only four combination vaccines are currently available in Japan, DTaP/sIPV, DTaP, DT, and MR, leading to complex infant vaccine scheduling. This study aims to investigate mothers' preferences with respect to combination vaccines for their children, should new combination vaccines become available that have not yet been launched in Japan or that will be developed in the future. We conducted a web-based, cross-sectional survey of 1,243 mothers who had at least one child between 2 months and 3 y of age. Mothers were recruited from an online survey panel of registered users. Their preferences were elicited using discrete choice experiments, the analyzed main effects model, and interactions using a mixed logit model. Mothers showed a preference for vaccines that prevented multiple diseases, had fewer injections per doctor visit, lower price, and lower risk of adverse events. Respondents valued a reduced risk of adverse events the most among all attributes in this study. The estimated monetary value of the willingness to pay for a 1% reduction in the risk of adverse events was ¥ 92,557 ($ 907). Therefore, if new combination vaccines are introduced, the risk of adverse events after vaccination is an especially important factor for mothers. While the safety of the vaccines themselves is required, health professionals should also inform mothers about the benefits and risks of vaccination, to allay mothers' concerns about vaccine safety.

Synchrony in serum antibody response to conserved proteins of Streptococcus pneumoniae in young children

Conserved Streptococcus pneumoniae (Spn) proteins are currently under investigation as vaccine candidates. We recently identified a subset of children prone to frequent acute otitis media (AOM) that we refer to as stringently-defined otitis prone (sOP). We investigated the synchrony of serum antibody responses against 5 Spn protein vaccine antigens, PhtD, LytB, PcpA, PhtE, and PlyD1 resulting from nasopharyngeal colonization and AOM in sOP children (49 observations) and non-otitis prone (NOP) children (771 observations). Changes in serum IgG and IgM were quantitated with ELISA. IgG antibody concentrations against PhtD, PcpA, and PlyD1 rose in synchrony in sOP and NOP children; that is, the proteins appeared equally and highly immunogenic in children at age 6 to 15 months and then leveled off in their rise at 15 to 25 months. In contrast, rises in concentrations to PhtE and LytB were significantly slower and had not peaked in children even at 25 months of age, consistent with lower immunogenicity. Serum IgM responses against PhtD and PlyD1 were in synchrony in children at age 6-25 months old. PcpA did not induce a significant increase of serum IgM response in children, suggesting that primary responses to PcpA occurred prior to children attaining age 6 months old. PhtD, PcpA, and Ply elicit a synchronous natural acquisition of serum antibody in young children suggesting that a trivalent Spn protein vaccine combining PhtD, PcpA, and PlyD1 would be less likely to display antigen competition when administered as a combination vaccine in young children.

Safety and immunogenicity of an investigational fully liquid hexavalent DTaP-IPV-Hep B-PRP-T vaccine at two, four and six months of age compared with licensed vaccines in Latin America

OBJECTIVE

This trial assessed the safety of a fully liquid investigational hexavalent DTaP-IPV-Hep B-PRP-T vaccine containing 10 μg Hansenula polymorpha-derived recombinant hepatitis B (hep B) antigen for primary vaccination of infants at 2, 4 and 6 months of age compared with licensed comparators.

METHODS

Participants received the DTaP-IPV-Hep B-PRP-T vaccine (group 1, N = 1422) or licensed DTwP-Hep B//Hib (Tritanrix-Hep B/Hib) and oral poliovirus vaccines (group 2, N = 711). The incidence of severe fever (≥ 39.6°C rectal equivalent) in the 2 groups was compared statistically; reactogenicity was evaluated from parental reports. Anti-Hep B antibody titers were measured in a subset of participants (no hepatitis B vaccination at birth) 1 month after dose 3.

RESULTS

The investigational vaccine was well tolerated. After any dose, fever (rectal equivalent temperature ≥ 38°C) was observed in 74.8% and 92.7% of participants in groups 1 and 2; severe fever was observed in 4.0% and 5.5% of participants. Solicited injection site and systemic reactions were numerically less frequent in group 1 than group 2, although this difference was not assessed statistically. In both groups, all participants included in the immunogenicity analysis achieved anti-Hep B ≥ 10 mIU/mL and ≥ 96.2% of participants achieved anti-Hep B ≥ 100 mIU/mL, although geometric mean titer was approximately 3-fold lower for the investigational vaccine.

CONCLUSION

This new, fully liquid acellular pertussis hexavalent vaccine demonstrated less reactogenicity than the licensed comparator whole cell pertussis vaccine and was highly immunogenic for the new Hep B valence.

Pediatric vaccines on the horizon

Vaccines have saved the lives of millions of children and continue to be essential interventions to control infectious diseases among people of all ages. The list of recommended vaccines for children has expanded in recent years; however, many viral, bacterial and parasitic infections remain a major cause of morbidity and mortality in children. Improved vaccines to prevent Streptococcus pneumoniae and Neisseria meningitidis infections in children will soon be available. Recent scientific advances are being applied to design new childhood vaccines affording enhanced efficacy, safety and tolerability. Financial barriers and other obstacles to adequate vaccine access need to be eliminated to assure coverage for all children and adolescents.

The impact of DTaP-IPV-HB vaccine on use of health services for young infants

BACKGROUND

In 2003, a pentavalent vaccine (diphtheria, tetanus and acellular pertussis, injectable polio and hepatitis B) was introduced into the childhood vaccination schedule. A premarketing study showed a higher incidence of fever than with the vaccines administered separately. Because fevers in young infants prompt medical evaluations, this study examines the impact of this vaccine (DTaP-IPV-HB) on subsequent use of health services.

METHODS

We compared use of health services among 6- to 10-week-old infants receiving DTaP-IPV-HB (n = 1776) with a historical control receiving the prior schedule (n = 2162) at an inner-city practice network. Data sources included a hospital immunization registry and medical records. Outcome measures were visits to the emergency department and ambulatory practices, fever, tests, antibiotics and hospitalizations. Outcomes were stratified by age (<8, 8-10 weeks) and days since vaccination (3, 7).

RESULTS

Infants vaccinated with DTaP-IPV-HB were more likely to visit the ED (1.2% versus 0.6%, P = 0.03) and receive tests (47.6% versus 8.3%, P = 0.03) within 3 days of vaccination compared with the controls. Multivariate analysis showed infants vaccinated with DTaP-IPV-HB had a 7-fold increased risk of receiving a full sepsis workup and a 3-fold increased risk of receiving antibiotics within 7 days of vaccination. Medical evaluations decreased over time after implementation of the DTaP-IPV-HB vaccine. Concurrently, the rate of vaccination for infants <8 weeks markedly dropped.

CONCLUSIONS

The DTaP-IPV-HB vaccine was associated with increased use of health services in the emergency department, but these associations lessened over time. These findings reveal a conflict between the obligation of timely and efficient vaccination with the medical management of febrile young infants.

Live bivalent vaccine for parainfluenza and influenza virus infections

Influenza and human parainfluenza virus infections are of both medical and economical importance. Currently, inactivated vaccines provide suboptimal protection against influenza, and vaccines for human parainfluenza virus infection are not available, underscoring the need for new vaccines against these respiratory diseases. Furthermore, to reduce the burden of vaccination, the development of multivalent vaccines is highly desirable. Thus, to devise a single vaccine that would elicit immune responses against both influenza and parainfluenza viruses, we used reverse genetics to generate an influenza A virus that possesses the coding region for the hemagglutinin/neuraminidase ectodomain of parainfluenza virus instead of the influenza virus neuraminidase. The recombinant virus grew efficiently in eggs but was attenuated in mice. When intranasally immunized with the recombinant vaccine, all mice developed antibodies against both influenza and parainfluenza viruses and survived an otherwise lethal challenge with either of these viruses. This live bivalent vaccine has obvious advantages over combination vaccines, and its method of generation could, in principle, be applied in the development of a "cocktail" vaccine with efficacy against several different infectious diseases.

One for all: newer combination vaccines in practice

As new combination vaccines are approved, practices must consider whether to switch. The decision is likely to be complex, involving everything from re-education of staff to recalculating the bottom line. At some point, however, change will be inevitable, driven principally by the need to add new vaccines to the schedule. In fall 2004, practitioners will be adding two doses of inactivated influenza vaccine to the infant schedule. More communities will be adding two doses of hepatitis A vaccine, which may become routine for all children at some point. We can hope as well for a meningococcal conjugate vaccine series, which, like Hib and PCV-7, would be administered by an infant's first birthday. In addition, there's the pentavalent bovine reassortant rotavirus vaccine (Rotateq) which, although given orally, will further crowd the schedule. The sooner we become comfortable with combination vaccines, the better.

Immunization issues for the 21st century

OBJECTIVE

Review and discuss major issues of vaccination and immunization. The development and application of vaccination and immunization is one of the most remarkable successes of the 20th century. This is true both in the United States and worldwide. In the United States, a number of vaccine-preventable diseases have been all but eliminated through the development of a recommended childhood immunization schedule by governmental and nongovernmental organizations, education of providers about these recommendations, and enforcement of these recommendations by school and day care entry mandates. Despite these successes, vaccine-preventable diseases continue to occur, in part because of missed opportunities by health care providers, antivaccine forces empowered by misguided mass media, and parental ignorance. Important aspects of the 2002 recommended childhood immunization schedule are reviewed, including: birth dose hepatitis B, diphtheria underimmunization and tetanus overimmunization, increasing pertussis disease, the success of conjugate vaccines, the change in poliovirus vaccines, measles vaccine and autism, the safety of varicella vaccine, and adult vaccination recommendations. Finally, future prospects for vaccination and immunization are discussed, including: combination vaccines, vaccines against new diseases such as rotavirus, new routes of delivery of immunizing agents, the use of computerized vaccine registries to prevent missed opportunities, and vaccines against bioterrorism agents.

CONCLUSIONS

A careful analysis of risk and benefit suggests that the benefit of vaccination far outweighs the risks from the utilization of immunizing agents. Vaccination delayed may be protection denied. The bottom line is that vaccines are good and disease is bad.

Neonatal jaundice, animal-induced injuries, and immunizations

The authors describe recent developments in three areas of pediatrics commonly encountered by the office practitioner. First, clinical assessment of jaundice remains critically important as "early discharge" of newborns continues. Practitioners constantly balance clinical realities with an evidence-based approach in the management and follow-up of neonatal hyperbilirubinemia. Second, given the frequent exposure of children to animals, a thorough understanding of animal bites, pet-borne infections, and rabies prophylaxis is essential for every pediatrician. Finally, immunization status remains one of our leading health indicators. Recent changes in the routine immunization schedule and a renewed emphasis on vaccine safety provide insight into the future direction of vaccinology.