Principles of Vaccine Licensure, Approval, and Recommendations for Use

The licensure and recommendation processes for vaccines are complex. In the United States, vaccines are licensed for the civilian and military populations on the basis of review of Biologics License Applications submitted to the Food and Drug Administration (FDA) by vaccine manufacturers. For FDA-licensed vaccines, the product label includes indications, contraindications, and precautions for each vaccine. Package inserts do not include recommendations for vaccine use from the Advisory Committee on Immunization Practices (ACIP). The ACIP is chartered as a federal advisory committee to provide expert external advice and guidance to the director of the Centers for Disease Control and Prevention on the use of vaccines and related agents for control of vaccine preventable diseases in the civilian and military populations of the United States. As an external advisory committee to the Centers for Disease Control and Prevention, the ACIP has no regulatory authority but the committee does have responsibility for approving vaccines to be covered under the Vaccines for Children program. To implement ACIP vaccine recommendations in the public and private sectors, a collaboration of federal, state, and local governments as well as private organizations dealing with public health, vaccine supply, vaccine administration, vaccine finance, outcomes monitoring, public perception, and public trust and support must work together. Issues including vaccine misinformation, declining community immunity (herd protection), and need for risk communication add stress to this complex and fragile system. This study describes the functions of and interactions between FDA and ACIP.

Protecting the Community Through Child Vaccination

The direct impact of vaccines on children is well described, but the major public health impact of indirect protection provided to the community by vaccines is underappreciated. Community protection occurs when vaccinated persons block the chain of transmission, protecting undervaccinated or unvaccinated susceptible community members by preventing exposure and limiting the spread of the pathogen through the community. Substantial declines in disease incidence have occurred shortly after implementing new childhood vaccines, including declines among vaccine-ineligible children, adolescents, and adults. Protection of susceptible community members depends on maintaining high vaccination rates. Improved recognition of community protection will strengthen childhood vaccination strategies that will protect our communities into the future.

Licensure, Approval, and Uptake of Vaccines in the United States

Immunization is one of the most effective public and private preventive health interventions, resulting in significant reductions in vaccine-preventable diseases and in substantial cost savings to the US healthcare system. Vaccine licensure, development of recommendations for use, and implementation of those recommendations leading to uptake, community protection, and effect on disease burden represent a complex system that requires collaboration in the areas of basic science, public health, vaccine delivery, outcome monitoring, and public perception. The Advisory Committee on Immunization Practices (ACIP) sets standards for immunization delivery for both public and private vaccine providers, and state immunization programs can use these ACIP recommendations to develop school immunization requirements.

Understanding FDA-Approved Labeling and CDC Recommendations for Use of Vaccines

Adherence to recommendations for the use of licensed vaccines ensures maximum individual and societal benefits from the national immunization program. The US Food and Drug Administration (FDA) licenses a vaccine once it determines that data submitted by the manufacturer reveal that the vaccine is safe and effective for its intended use. For each US-licensed vaccine, the FDA-approved prescribing information contains detailed information for health care providers to ensure safe and effective use. Centers for Disease Control and Prevention recommendations for the use of a licensed vaccine often are based on additional considerations, such as disease epidemiology, public acceptance, vaccine supply, and cost. Our objective in this article is to explain the reasons for the differences between FDA-approved prescribing information and Centers for Disease Control and Prevention recommendations for vaccine use.

2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea

These guidelines are intended for use by healthcare professionals who care for children and adults with suspected or confirmed infectious diarrhea. They are not intended to replace physician judgement regarding specific patients or clinical or public health situations. This document does not provide detailed recommendations on infection prevention and control aspects related to infectious diarrhea.

2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea

These guidelines are intended for use by healthcare professionals who care for children and adults with suspected or confirmed infectious diarrhea. They are not intended to replace physician judgement regarding specific patients or clinical or public health situations. This document does not provide detailed recommendations on infection prevention and control aspects related to infectious diarrhea.

FDA licensure of and ACIP recommendations for vaccines

Many healthcare providers are not familiar with the Food and Drug Administration (FDA) vaccine licensure process, the Advisory Committee on Immunization Practices (ACIP) vaccine recommendation process, and how FDA vaccine licensure and ACIP recommendations are related. Vaccines for use in the United States military and civilian populations are licensed by the FDA by several potential pathways but use of licensed vaccines in the civilian population should be based on recommendations made by the ACIP. In performing these distinct activities, FDA and ACIP function under different mandates. In this article, we discuss whether the FDA licensure pathways used to approve a vaccine impacts ACIP recommendation categories for vaccines licensed from 2006 to 2016.

Lessons Learned From Making and Implementing Vaccine Recommendations in the U.S

After publication of certain vaccine recommendations made by the Advisory Committee on Immunization Practices, several unexpected events have occurred during implementation of these recommendations. These have included changes in recommendations following adverse events involved with a particular vaccine and the conferral of community protection as an offshoot of vaccination of a specific population. Vaccine shortages and hesitancy have also been proven impediments to full implementation, and vaccine recommendations have not gone unaffected by either public perception of a vaccine or by cost considerations.

The history of the United States Advisory Committee on Immunization Practices (ACIP)

The United States Advisory Committee on Immunization Practices (ACIP) is a federal advisory committee that develops written recommendations for use of vaccines licensed by the Food and Drug Administration (FDA) for the U.S. civilian population. Vaccine development and disease outbreaks contributed to the need for a systematized, science-based, formal mechanism for establishing national immunization policy in this country. Formed in 1964, the ACIP was charged with this role. The committee has undergone significant changes in structure and operational activities during its 50-year history. The ACIP works closely with many liaison organizations to develop its immunization recommendations, which are harmonized among key professional medical societies. ACIP vaccine recommendations form two immunization schedules, which are updated annually: (1) the childhood and adolescent immunization schedule and (2) the adult immunization schedule. Today, once ACIP recommendations are adopted by the Director of the Centers for Disease Control and Prevention and the Secretary of the Department of Health and Human Services, these recommendations are published in Morbidity and Mortality Weekly Report (MMWR), become official policy, and are incorporated into the appropriate immunization schedule.

History and evolution of the advisory committee on immunization practices--United States, 1964-2014

The Advisory Committee on Immunization Practices (ACIP) is chartered as a federal advisory committee to provide expert external advice to CDC and the Secretary of the U.S. Department of Health and Human Services (DHHS) on the use of vaccines in the civilian population of the United States. This report summarizes the evolution of ACIP over the 50 years since its establishment in 1964 by the Surgeon General of the U.S. Public Health Service (USPHS).

The Red Book through the ages

The first edition of the Red Book was published in 1938. Since then, there have been numerous advances in the fields of infectious diseases and public health that have decreased morbidity and mortality of infants, children, and adolescents. Over the years, emerging pathogens and disease complexes have been described, sophisticated diagnostic techniques developed, advances in antimicrobial therapy have occurred, and immunizations have been implemented to prevent previously deadly diseases. Of the 18 diseases or organisms in the 1938 edition, 13 are now vaccine-preventable. Since inception of the Red Book, the aims of the editors have been to keep pace with these innovations and to continue to inform the medical community. These goals have made the Red Book a fundamental resource for pediatricians and other health care professionals in terms of guiding diagnosis, therapy, and prevention of infectious diseases. The list of 18 diseases or organisms originally described in the 1938 Red Book has expanded to include over 160 diseases or organisms in the 2012 edition. The pace of biomedical discovery, as well as the amount of information available and the number of methods for its delivery, will continue to accelerate in the future. Integration of information into future editions of the Red Book will ensure that practitioners continue to rely on the Red Book in its various electronic formats for clinical guidance and support.

Vaccines in the pipeline: the path from development to use in the United States

New vaccines in the United States go through a complex process on their path from development to the domestic market involving an intricate partnership of public and private agencies and organizations. This process includes licensure by the US Food and Drug Administration, the development of recommendations by the Advisory Committee on Immunization Practices, and safety oversight post-licensure. This article examines the roles of the US Food and Drug Administration and the Centers for Disease Control and Prevention as well as certain professional organizations in governing the testing, marketing, and usage of new vaccines. Vaccines currently in development to treat numerous infectious and noninfectious diseases are also examined and compared with frameworks of domestic vaccine development prioritization, past and present, as assessed by the Institute of Medicine.

How to communicate with vaccine-hesitant parents

Development of safe and effective vaccines is one the greatest medical triumphs. However, despite high immunization rates in the United States, 85% of health care providers (HCPs) will have a parent refuse a vaccine for his or her child each year. HCPs have the greatest influence on a parent's decision to vaccinate his or her child. To effectively communicate with vaccine-hesitant parents, HCPs must first understand the concerns of parents regarding immunization and understand influences that can lead to misinformation about the safety and effectiveness of vaccines. HCPs should establish an open, nonconfrontational dialogue with vaccine-hesitant parents at an early stage and provide unambiguous, easily comprehensible answers about known vaccine adverse events and provide accurate information about vaccination. Personal stories and visual images of patients and parents affected by vaccine-preventable diseases and reports of disease outbreaks serve as useful reminders of the need to maintain high immunization rates. Ongoing dialogue including provider recommendations may successfully reassure vaccine-hesitant parents that immunization is the best and safest option for their child.

Immunization programs for infants, children, adolescents, and adults: clinical practice guidelines by the Infectious Diseases Society of America

Evidence-based guidelines for immunization of infants, children, adolescents, and adults have been prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). These updated guidelines replace the previous immunization guidelines published in 2002. These guidelines are prepared for health care professionals who care for either immunocompetent or immunocompromised people of all ages. Since 2002, the capacity to prevent more infectious diseases has increased markedly for several reasons: new vaccines have been licensed (human papillomavirus vaccine; live, attenuated influenza vaccine; meningococcal conjugate vaccine; rotavirus vaccine; tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis [Tdap] vaccine; and zoster vaccine), new combination vaccines have become available (measles, mumps, rubella and varicella vaccine; tetanus, diphtheria, and pertussis and inactivated polio vaccine; and tetanus, diphtheria, and pertussis and inactivated polio/Haemophilus influenzae type b vaccine), hepatitis A vaccines are now recommended universally for young children, influenza vaccines are recommended annually for all children aged 6 months through 18 years and for adults aged > or = 50 years, and a second dose of varicella vaccine has been added to the routine childhood and adolescent immunization schedule. Many of these changes have resulted in expansion of the adolescent and adult immunization schedules. In addition, increased emphasis has been placed on removing barriers to immunization, eliminating racial/ethnic disparities, addressing vaccine safety issues, financing recommended vaccines, and immunizing specific groups, including health care providers, immunocompromised people, pregnant women, international travelers, and internationally adopted children. This document includes 46 standards that, if followed, should lead to optimal disease prevention through vaccination in multiple population groups while maintaining high levels of safety.

Associations between childhood vaccination status and medical practice characteristics among white, black, and Hispanic children

BACKGROUND

The purpose of the study was to identify and understand associations between characteristics of medical practices where immunization services are delivered and vaccination status among white, black, and Hispanic children aged less than 19 months.

METHODS

Eighty pediatric and family physicians participated in a physician-patient encounters survey that included 684 children aged less than 19 months who received at least 1 vaccination during a randomly selected week in 2003.

RESULTS

According to physicians' responses to survey questions, white children who used large medical practices, and black and Hispanic children who used practices, all enrolled in the Vaccine for Children (VFC) program, were more likely to receive vaccines at the recommended age, but Hispanic children who used large Medicaid practices were less likely to receive them at the recommended age. White children who used medical practices that had a large minority patient population were more likely to have completely missed whole series of vaccines.

CONCLUSION

Medical practice characteristics varied in importance as determinants of childhood vaccination among white, black, and Hispanic children. Understanding how type of medical practice and other medical practice characteristics may impact the receipt of timely preventive health services is vital to improving health care access in underserved populations.

Expert review of the evidence base for prevention of travelers' diarrhea

The most frequent illness among persons traveling from developed to developing countries is travelers' diarrhea. Travelers to high-risk regions traditionally have been educated to exercise care in food and beverage selection. Innovative research is needed to identify ways to motivate people to exercise this care and to determine its value. Chemoprophylaxis can be recommended for certain groups while monitoring for safety, drug resistance, and efficacy against all forms of bacterial diarrhea. Research to evaluate the value of immunoprophylaxis is recommended. In the following document, the authors used an evidence base when available to determine strength and quality of evidence and when data were lacking, the panel experts provided consensus opinion.

Immunization policy development in the United States: the role of the Advisory Committee on Immunization Practices

The Advisory Committee on Immunization Practices (ACIP) consists of 15 experts in immunization and related fields, selected by the Secretary of the U.S. Department of Health and Human Services, to provide advice and guidance on control of vaccine-preventable diseases. In its role as a federal advisory committee, the ACIP develops written recommendations, subject to approval of the Director of the Centers for Disease Control and Prevention, for administration of U.S. Food and Drug Administration-licensed vaccines to children, adolescents, and adults in the U.S. civilian population. On the basis of careful review of available scientific data, including disease morbidity and mortality in the general U.S. population and in specific risk groups, vaccine safety and efficacy, cost-effectiveness, and related factors, the ACIP recommends vaccines and age for vaccine administration, number of doses and dosing interval, and precautions and contraindications. The ACIP works closely with several liaison organizations, including the American College of Physicians, to develop immunization recommendations that are harmonized among key professional medical organizations in the United States. This report includes a description of the member composition of the ACIP, the degree to which Committee members are screened for conflicts of interest, the workgroups that gather information before full Committee consideration, and the process and types of evidence used to formulate recommendations.

Exposure to nontraditional pets at home and to animals in public settings: risks to children

Exposure to animals can provide many benefits during the growth and development of children. However, there are potential risks associated with animal exposures, including exposure to nontraditional pets in the home and animals in public settings. Educational materials, regulations, and guidelines have been developed to minimize these risks. Pediatricians, veterinarians, and other health care professionals can provide advice on selection of appropriate pets as well as prevention of disease transmission from nontraditional pets and when children contact animals in public settings.

General recommendations on immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP)

This report is a revision of General Recommendations on Immunization and updates the 2002 statement by the Advisory Committee on Immunization Practices (ACIP) (CDC. General recommendations on immunization: recommendations of the Advisory Committee on Immunization Practices and the American Academy of Family Physicians. MMWR 2002;51[No. RR-2]). This report is intended to serve as a general reference on vaccines and immunization. The principal changes include 1) expansion of the discussion of vaccination spacing and timing; 2) an increased emphasis on the importance of injection technique/age/body mass in determining appropriate needle length; 3) expansion of the discussion of storage and handling of vaccines, with a table defining the appropriate storage temperature range for inactivated and live vaccines; 4) expansion of the discussion of altered immunocompetence, including new recommendations about use of live-attenuated vaccines with therapeutic monoclonal antibodies; and 5) minor changes to the recommendations about vaccination during pregnancy and vaccination of internationally adopted children, in accordance with new ACIP vaccine-specific recommendations for use of inactivated influenza vaccine and hepatitis B vaccine. The most recent ACIP recommendations for each specific vaccine should be consulted for comprehensive discussion. This report, ACIP recommendations for each vaccine, and other information about vaccination can be accessed at CDC's National Center for Immunization and Respiratory Diseases (proposed) (formerly known as the National Immunization Program) website at http//:www.cdc.gov/nip.

Association between health care providers' influence on parents who have concerns about vaccine safety and vaccination coverage

OBJECTIVES

Parents who have concerns about vaccine safety may be reluctant to have their children vaccinated. The purpose of this study was to explore how vaccination coverage among children 19 to 35 months of age is associated with health care providers' influence on parents' decision to vaccinate their children, and with parents' beliefs about vaccine safety.

METHODS

Parents of 7695 children 19 to 35 months of age sampled by the National Immunization Survey were administered the National Immunization Survey Parental Knowledge Module between the third quarter of 2001 and the fourth quarter of 2002. Health care providers were defined as a physician, nurse, or any other type of health care professional. Parents provided responses that summarized the degree to which they believed vaccines were safe, and the influence providers had on their decisions to vaccinate their children. Children were determined to be up-to-date if their vaccination providers reported administering > or = 4 doses of diphtheria and tetanus toxoids and acellular pertussis vaccine, > or = 3 doses of polio vaccine, > or = 1 dose of measles-mumps-rubella vaccine, > or = 3 doses of Haemophilus influenzae type b vaccine, and > or = 3 doses of hepatitis B vaccine.

RESULTS

Of all of the parents, 5.7% thought that vaccines were not safe, and 21.5% said that their decision to vaccinate their children was not influenced by a health care provider. Compared with parents who responded that providers were not influential in their decision to vaccinate their children, parents who responded that providers were influential were twice as likely to respond that vaccines were safe for children. Among children whose parents believed that vaccines were not safe, those whose parents' decision to vaccinate was influenced by a health care provider had an estimated vaccination coverage rate that was significantly higher than the estimated coverage rate among children whose parents' decision was not influenced by a health care provider (74.4% vs 50.3%; estimated difference: 24.1%).

CONCLUSIONS

Health care providers have a positive influence on parents to vaccinate their children, including parents who believe that vaccinations are unsafe. Physicians, nurses, and other health care professionals should increase their efforts to build honest and respectful relationships with parents, especially when parents express concerns about vaccine safety or have misconceptions about the benefits and risks of vaccinations.

Parent attitudes toward immunizations and healthcare providers the role of information

BACKGROUND

Lack of information has been associated with patient anxiety or concern in a number of healthcare areas.

OBJECTIVES

(1) Identify the proportion of parents who agreed, were neutral, and disagreed that they had access to enough information to make a decision about immunizing their child; (2) examine how parents who agreed and disagreed differed with respect to sociodemographic characteristics, and their attitudes about immunizations, their child's healthcare provider, immunization requirements/exemptions, and immunization policymakers; and (3) identify if differences exist in specific immunization concerns.

METHODS

A sample of parents with at least one child aged < or =6 years (n=642) was analyzed using data from the HealthStyles survey conducted during July and August 2003. Odds ratios and the Mantel-Haenszel chi-square test were used for analysis.

RESULTS

Response rate for HealthStyles was 69% (4035/5845). The largest proportion of parents agreed they had access to enough information (67%) compared to parents who were neutral (20%) or who disagreed (13%). Compared to parents who agreed, parents who disagreed were more likely to be less confident in the safety of childhood vaccines (odds ratio [OR]=5.4, 95% confidence interval [CI]=3.3-8.9), and to disagree that their child's main healthcare provider is easy to talk to (OR=10.3, 95% CI=3.7-28.1). There was a significant linear trend in the percentage of parents expressing immunization concerns among those who agreed, were neutral, and who disagreed they had access to enough information (p<0.05; df=1).

CONCLUSIONS

While most parents agreed that they had access to enough immunization information, approximately a third did not. Perceived lack of information was associated with negative attitudes about immunizations and toward healthcare providers. Basic information about the benefits and risks of vaccines presented by a trusted provider could go a long way toward maintaining and/or improving confidence in the immunization process.

Immunizations in the United States: a rite of passage

Today, vaccination is a cornerstone of pediatric preventive health care and a rite of passage for nearly all of the approximately 11,000 infants born daily in the United States. This article reviews the US immunization program with an emphasis on its role in ensuring that vaccines are effective, safe, and available and highlights several new vaccines and recommendations that will affect the health of children and adolescents and the practice of pediatric medicine in future decades.

Who's calling the shots? Pediatricians' adherence to the 2001-2003 pneumococcal conjugate vaccine-shortage recommendations

BACKGROUND

A national shortage of heptavalent pneumococcal conjugate vaccine (PCV7) occurred from September 2001 through May 2003. In December 2001 and January 2002, the Advisory Committee on Immunization Practices and the American Academy of Pediatrics (AAP) issued PCV7-shortage recommendations, emphasizing that all health care providers decrease the number of doses for healthy children so that more children could receive some PCV7.

OBJECTIVES

We assessed (1) how the PCV7 shortage affected pediatricians, (2) whether children in the public and private sectors were vaccinated differently during the shortage, (3) pediatricians' knowledge of and adherence to the Advisory Committee on Immunization Practices/AAP recommendations, (4) and what factors were associated with nonadherence to the recommendations.

METHODS

We conducted a cross-sectional mail survey of 2500 US physician-members of the AAP from November 2002 through March 2003; physicians providing childhood immunizations were eligible. We asked about PCV7-shortage experience, assessed recommendation adherence through clinical scenarios, and modeled potential factors associated with reported nonadherence to the recommendation to defer the fourth PCV7 dose.

RESULTS

Of 2478 surveys sent to valid addresses, 1412 (57%) completed surveys were received; 946 (67%) of these were from eligible pediatricians. Overall, 79% experienced a PCV7 shortage, 94% reported being aware of the recommendations, and 42% reported barriers to recommendation adherence. Ninety-four percent reported vaccinating 6-month-old infants with private or public insurance in the same manner. As recommended, 91% reported fully vaccinating high-risk patients. Contrary to recommendations, 49% reported sometimes or always administering the fourth PCV7 dose to healthy children 12 to 15 months old; their reasons included recurrent otitis media, childcare attendance, and parental desire. Controlling for other characteristics, pediatricians who had no PCV7 shortage in their practices were significantly more likely to report administering the fourth dose than pediatricians who had a shortage (odds ratio [OR]: 3.67; 95% confidence interval [CI]: 2.40-5.63). Other factors associated with nonadherence were being in solo private practice (OR: 2.18; 95% CI: 1.26-3.77) or being male (OR: 1.51; 95% CI: 1.08-2.12). Among pediatricians deferring PCV7, 36% reported having no system to track children for whom PCV7 was deferred.

CONCLUSIONS

Many pediatricians, both with and without a PCV7 shortage, administered more PCV7 doses than recommended. Pediatricians without a shortage were less likely to limit use, which suggests that they might have focused on the perceived value of administering the full schedule to their patients in preference to broader public health goals. Providing more information to physicians on the effectiveness of a fewer-dose schedule and the risk of disease when vaccine is deferred and educating parents might increase adherence to recommendations and achieve more equitable coverage during vaccine shortages.

Timeliness of childhood vaccinations in the United States: days undervaccinated and number of vaccines delayed

CONTEXT

Only 18% of children in the United States receive all vaccinations at the recommended times or acceptably early.

OBJECTIVE

To determine the extent of delay of vaccination during the first 24 months of life.

DESIGN, SETTING, AND PARTICIPANTS

The 2003 National Immunization Survey was conducted by random-digit dialing of households and mailings to vaccination providers to estimate vaccination coverage rates for US children aged 19 to 35 months. Data for this study were limited to 14,810 children aged 24 to 35 months.

MAIN OUTCOME MEASURES

Cumulative days undervaccinated during the first 24 months of life for each of 6 vaccines (diphtheria and tetanus toxoids and acellular pertussis; poliovirus; measles, mumps, and rubella; Haemophilus influenzae type b; hepatitis B; and varicella) and all vaccines combined, number of late vaccines, and risk factors for severe delay of vaccination.

RESULTS

Children were undervaccinated a mean of 172 days (median, 126 days) for all vaccines combined during their first 24 months of life. Approximately 34% were undervaccinated for less than 1 month and 29% for 1 to 6 months, while 37% were undervaccinated for more than 6 months. Vaccine-specific undervaccination of more than 6 months ranged from 9% for poliovirus vaccine to 21% for Haemophilus influenzae type b vaccine. An estimated 25% of children had delays in receipt of 4 or more of the 6 vaccines. Approximately 21% of children were severely delayed (undervaccinated for more than 6 months and for > or vaccines). Factors associated with severe delay included having a mother who was unmarried or who did not have a college degree, living in a household with 2 or more children, being non-Hispanic black, having 2 or more vaccination providers, and using public vaccination provider(s).

CONCLUSIONS

More than 1 in 3 children were undervaccinated for more than 6 months during their first 24 months of life and 1 in 4 children were delayed for at least 4 vaccines. Standard measures of vaccination coverage mask substantial shortfalls in ensuring that recommendations are followed regarding age at vaccination throughout the first 24 months of life.

Prebiotic effect of fructo-oligosaccharide supplemented term infant formula at two concentrations compared with unsupplemented formula and human milk

BACKGROUND

Human milk components, including oligosaccharides, affect the gastrointestinal flora of infants. Previous studies in adults have demonstrated that fructo-oligosaccharides increase potentially beneficial fecal bacteria, including bifidobacteria. The purpose of this study was to determine the prebiotic effect of infant formula supplemented with fructo-oligosaccharides.

METHODS

Healthy term infants 2 to 6 weeks of age were enrolled in a 5-week, prospective, randomized, crossover, single-site study with a nonrandomized human milk comparator group. Washout weeks preceded and followed a week of feeding with fructo-oligosaccharide-supplemented formula (1.5 or 3.0 g/L). Stool specimens were quantitatively cultured weekly for bacteroides, lactobacilli, bifidobacteria, clostridia and enterococci and were tested for Clostridium difficile toxin.

RESULTS

Seventy-two of 87 infants completed the trial; 58 were formula fed and 14 were human milk fed. Mean counts of bifidobacteria and lactobacilli were similar in all groups at entry and no group experienced a significant change in counts with fructo-oligosaccharide supplementation. After 7 days of fructo-oligosaccharide supplementation the bifidobacteria counts were greater in the 1.5 g/L fructo-oligosaccharide formula group than in the human milk fed or 3.0 g/L fructo-oligosaccharide formula groups. Formula-fed infants had higher counts of enterococci and bacteroides before fructo-oligosaccharide supplementation, and these counts did not change after supplementation. Clostridium counts increased 7 days after supplementation in the 1.5 g/L fructo-oligosaccharide formula group (P = 0.0356). No human milk fed infants had C. difficile toxin in stools. Fructo-oligosaccharide (3.0 g/L) supplementation resulted in more frequent and significantly softer stools.

CONCLUSIONS

Infant formula supplemented with 1.5 or 3.0 g/L fructo-oligosaccharides was safe but had minimal effect on fecal flora and C. difficile toxin.

Antimicrobial resistance among enteric pathogens

Diarrhea is a major cause of morbidity and mortality in infants and children worldwide. Use of antimicrobial therapy in children with bacterial diarrhea involves consideration of advantages and limitations of use of appropriate agents in the general population and in specific hosts. Antimicrobial agents for bacterial diarrhea should be prescribed with an appreciation of limitations including antimicrobial resistance. Studies from many countries have reported resistance to Campylobacter jejuni, Campylobacter coli, Shigella species, Salmonella species, and shiga toxin producing Escherichia coli. In many geographic areas of the world including the United States, resistance patterns have demonstrated a consistent increase over the course of time, with resistance occurring to several classes of antimicrobial agents. Resistance patterns are influenced by geographic location, year isolates were obtained, classes of antimicrobial agents, pressure exerted by antimicrobial use, and source of the isolate. Because antimicrobial resistance among enteric pathogens is a common finding, has increased over time, and varies by geographic location, constant monitoring of susceptibility patterns is necessary for selection of appropriate antimicrobial agents for therapy when indicated.

Human milk contains elements that block binding of noroviruses to human histo-blood group antigens in saliva

Noroviruses (NVs) recognize human histo-blood group antigens (HBGAs) as receptors. We characterized the interaction of human milk samples with recombinant virus-like particles representing VA387, Norwalk, VA207, and MOH. Milk samples from 60 healthy women were tested for human HBGAs and for their ability to block the binding of NVs. Fifty-four women were secretors (Se+), and 6 were nonsecretors (Se-). No women had detectable A or B antigens in their milk samples. All 54 Se+ milk samples, but 0 of 6 Se- milk samples, blocked VA387 and Norwalk virus (Se+ binders) from binding to saliva samples. All 6 Lewis-positive Se- milk samples blocked binding to VA207, and variable blocking activities were exhibited by the Se+ milk samples. No milk samples blocked the binding of MOH to A and B antigens. Secretor and Lewis, but not A or B antigens, were present in human milk and were responsible for blocking NV binding to receptors and therefore are likely to be decoy receptors that protect breast-fed infants from NV infection.

Thimerosal-containing vaccines and autistic spectrum disorder: a critical review of published original data

OBJECTIVE

The issue of thimerosal-containing vaccines as a possible cause of autistic spectrum disorders (ASD) and neurodevelopmental disorders (NDDs) has been a controversial topic since 1999. Although most practitioners are familiar with the controversy, many are not familiar with the type or quality of evidence in published articles that have addressed this issue. To assess the quality of evidence assessing a potential association between thimerosal-containing vaccines and autism and evaluate whether that evidence suggests accepting or rejecting the hypothesis, we systematically reviewed published articles that report original data pertinent to the potential association between thimerosal-containing vaccines and ASD/NDDs.

METHODS

Articles for analysis were identified in the National Library of Medicine's Medline database using a PubMed search of the English-language literature for articles published between 1966 and 2004, using keywords thimerosal, thiomersal, mercury, methylmercury, or ethylmercury alone and combined with keywords autistic disorder, autistic spectrum disorder, and neurodevelopment. In addition, we used the "related links" option in PubMed and reviewed the reference sections in the identified articles. All original articles that evaluated an association between thimerosal-containing vaccines and ASD/NDDs or pharmacokinetics of ethylmercury in vaccines were included.

RESULTS

Twelve publications that met the selection criteria were identified by the literature search: 10 epidemiologic studies and 2 pharmacokinetic studies of ethylmercury. The design and quality of the studies showed significant variation. The preponderance of epidemiologic evidence does not support an association between thimerosal-containing vaccines and ASD. Epidemiologic studies that support an association are of poor quality and cannot be interpreted. Pharmacokinetic studies suggest that the half-life of ethylmercury is significantly shorter when compared with methylmercury.

CONCLUSIONS

Studies do not demonstrate a link between thimerosal-containing vaccines and ASD, and the pharmacokinetics of ethylmercury make such an association less likely. Epidemiologic studies that support a link demonstrated significant design flaws that invalidate their conclusions. Evidence does not support a change in the standard of practice with regard to administration of thimerosal-containing vaccines in areas of the world where they are used.

Human milk oligosaccharides are associated with protection against diarrhea in breast-fed infants

OBJECTIVE

To determine the association between maternal milk levels of 2-linked fucosylated oligosaccharide and prevention of diarrhea as a result of Campylobacter, caliciviruses, and diarrhea of all causes in breast-fed infants.

STUDY DESIGN

Data and banked samples were analyzed from 93 breast-feeding mother-infant pairs who were prospectively studied during 1988-1991 from birth to 2 years with infant feeding and diarrhea data collected weekly; diarrhea was diagnosed by a study physician. Milk samples obtained 1 to 5 weeks postpartum were analyzed for oligosaccharide content. Data were analyzed by Poisson regression.

RESULTS

Total 2-linked fucosyloligosaccharide in maternal milk ranged from 0.8 to 20.8 mmol/L (50%-92% of milk oligosaccharide). Moderate-to-severe diarrhea of all causes (n=77 cases) occurred less often (P=.001) in infants whose milk contained high levels of total 2-linked fucosyloligosaccharide as a percent of milk oligosaccharide. Campylobacter diarrhea (n=31 cases) occurred less often (P=.004) in infants whose mother's milk contained high levels of 2'-FL, a specific 2-linked fucosyloligosaccharide, and calicivirus diarrhea (n=16 cases) occurred less often (P=.012) in infants whose mother's milk contained high levels of lacto-N-difucohexaose (LDFH-I), another 2-linked fucosyloligosaccharide.

CONCLUSION

This study provides novel evidence suggesting that human milk oligosaccharides are clinically relevant to protection against infant diarrhea.

Genetic diversity among sapoviruses

Norovirus and Sapovirus are two genera of the family Caliciviridae that contain viruses that can cause acute gastroenteritis in humans. Noroviruses (NOR) are genetically highly diverse but limited studies of the genetic diversity of sapoviruses (SAP) have been reported. In this study we characterized twenty-five SAP detected in our laboratory from outbreaks or sporadic cases of acute gastroenteritis in children from different geographical locations and in adults involved in a cruise ship outbreak investigation and a nursing home outbreak. Based on significant differences of partial RNA polymerase sequences (278-286 nt), the 25 strains were grouped into 12 genetic clusters, including 9 potential new clusters. Extended sequence analysis of the capsid gene of selected strains representing five potential new clusters supported this grouping. Four strains (Hou7-1181/90, Mex340/90, Cruise ship/00 and Argentina39) had <84% amino acid (aa) identity to each other and to the published sequences in the GenBank. Mex14917/00 was almost identical to Stockholm/97/SE whose RNA polymerase sequence was unknown. Phylogenetic and distance analyses of the capsid region of the four new strains showed that Hou7-1181/90 and Argentina39 represent two new genogroups and Mex340/90 and Cruise ship/00 belong to two new clusters within the London/92 genogroup. Thus, based on the capsid sequences we propose to classify the currently known SAP into nine genetic clusters within five genogroups, including one genogroup that is represented by an animal calicivirus, the porcine enteric calicivirus (PEC).

Evaluation of a lactation support service in a children's hospital neonatal intensive care unit

Breastfeeding hospitalized infants can be difficult. The authors assessed the effectiveness of an International Board Certified Lactation Consultants (IBCLC) service to increase the proportion of infants given their own mother's milk (OMM) in a children's hospital neonatal intensive care unit (NICU). The charts of 350 randomly selected patients admitted the year before and after implementation of the service in July 1997 were abstracted. Factors significantly associated with infants being given OMM included infant sex, ethnicity, length of NICU stay, and 5-minute Apgar score. After comparison of the periods before and after program implementation, the proportion of NICU infants ever given their OMM was found to have increased from 31% to 47% (P = .002). This increase differed significantly in relation to infants' clinical status and/or management (5-minute Apgar score, length of NICU stay, and age at NICU admission) but not in relation to maternal factors. Mothers with infants in the NICU should have access to lactation counseling.

Noroviruses bind to human ABO, Lewis, and secretor histo-blood group antigens: identification of 4 distinct strain-specific patterns

We characterized the binding of 8 Noroviruses (NORs) to histo-blood group antigens (HBGAs) in human saliva using recombinant NOR (rNOR) capsid proteins. Among the 8 rNORs tested, 6 formed viruslike particles (VLPs) when the capsid proteins were expressed in insect cells, all of which revealed variable binding activities with saliva; the remaining 2 rNORs did not form VLPs, and the proteins did not bind, or bound weakly, to saliva. Four distinct binding patterns were associated with different histo-blood types, defined by Lewis, secretor, and ABO types. Three patterns (VA387, NV, and MOH) recognized secretors, and 1 pattern (VA207) recognized Lewis-positive nonsecretors. The 3 secretor-recognizing patterns were defined as A/B (MOH), A/O (NV), and A/B/O (VA387) binders. Oligosaccharides containing the Lewis and ABH antigenic epitopes were involved in binding. Our findings suggest that different strains of NORs may recognize different human HBGAs on intestinal epithelial cells as receptors for infection.