Molecular signatures of antibody responses derived from a systems biology study of five human vaccines.

Many vaccines induce protective immunity via antibodies. Systems biology approaches have been used to determine signatures that can be used to predict vaccine-induced immunity in humans, but whether there is a 'universal signature' that can be used to predict antibody responses to any vaccine is unknown. Here we did systems analyses of immune responses to the polysaccharide and conjugate vaccines against meningococcus in healthy adults, in the broader context of published studies of vaccines against yellow fever virus and influenza virus. To achieve this, we did a large-scale network integration of publicly available human blood transcriptomes and systems-scale databases in specific biological contexts and deduced a set of transcription modules in blood. Those modules revealed distinct transcriptional signatures of antibody responses to different classes of vaccines, which provided key insights into primary viral, protein recall and anti-polysaccharide responses. Our results elucidate the early transcriptional programs that orchestrate vaccine immunity in humans and demonstrate the power of integrative network modeling.

Hurricane Evacuation Laws in Eight Southern U.S. Coastal States - December 2018.

National Preparedness month is observed every September as a public service reminder of the importance of personal and community preparedness for all events; it coincides with the peak of the hurricane season in the United States. Severe storms and hurricanes can have long-lasting effects at all community levels. Persons who are prepared and well-informed are often better able to protect themselves and others (1). Major hurricanes can devastate low-lying coastal areas and cause injury and loss of life from storm surge, flooding, and high winds (2). State and local government entities play a significant role in preparing communities for hurricanes and by evacuating coastal communities before landfall to reduce loss of life from flooding, wind, and power outages (3). Laws can further improve planning and outreach for catastrophic events by ensuring explicit statutory authority over evacuations of communities at risk (4). State evacuation laws vary widely and might not adequately address information and communication flows to reach populations living in disaster-prone areas who are at risk. To understand the range of evacuation laws in coastal communities that historically have been affected by hurricanes, a systematic policy scan of the existing laws supporting hurricane evacuation in eight southern coastal states (Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, and Texas) was conducted. After conducting a thematic analysis, this report found that all eight states have laws to execute evacuation orders, traffic control (egress/ingress), and evacuation to shelters. However, only four of the states have laws related to community outreach, delivery of public education programs, and public notice requirements. The findings in this report suggest a need for authorities in hurricane-prone states to review how to execute evacuation policies, particularly with respect to community outreach and communication to populations at risk. Implementation of state evacuation laws and policies that support hurricane evacuation management can help affected persons avoid harm and enhance community resiliency (5). Newly emerging and re-emerging infectious diseases, such as SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), have and will continue to additionally challenge hurricane evacuations.

School District Crisis Preparedness, Response, and Recovery Plans - United States, 2012.

The unique characteristics of children dictate the need for school-based all-hazards response plans during natural disasters, emerging infectious diseases, and terrorism (1-3). Schools are a critical community institution serving a vulnerable population that must be accounted for in public health preparedness plans; prepared schools are adopting policies and plans for crisis preparedness, response, and recovery (2-4). The importance of having such plans in place is underscored by the development of a new Healthy People 2020 objective (PREP-5) to "increase the percentage of school districts that require schools to include specific topics in their crisis preparedness, response, and recovery plans" (5). Because decisions about such plans are usually made at the school district level, it is important to examine district-level policies and practices. Although previous reports have provided national estimates of the percentage of districts with policies and practices in place (6), these estimates have not been analyzed by U.S. Census region* and urbanicity.(†) Using data from the 2012 School Health Policies and Practices Study (SHPPS), this report examines policies and practices related to school district preparedness, response, and recovery. In general, districts in the Midwest were less likely to require schools to include specific topics in their crisis preparedness plans than districts in the Northeast and South. Urban districts tended to be more likely than nonurban districts to require specific topics in school preparedness plans. Southern districts tended to be more likely than districts in other regions to engage with partners when developing plans. No differences in district collaboration (with the exception of local fire department engagement) were observed by level of urbanicity. School-based preparedness planning needs to be coordinated with interdisciplinary community partners to achieve Healthy People 2020 PREP-5 objectives for this vulnerable population.

Naturally acquired antibodies against Haemophilus influenzae type a in Aboriginal adults, Canada.

In the post-Haemophilus influenzae type b (Hib) vaccine era that began in the 1980's, H. influenzae type a (Hia) emerged as a prominent cause of invasive disease in North American Aboriginal populations. To test whether a lack of naturally acquired antibodies may underlie increased rates of invasive Hia disease, we compared serum bactericidal activity against Hia and Hib and IgG and IgM against capsular polysaccharide between Canadian Aboriginal and non-Aboriginal healthy and immunocompromised adults. Both healthy and immunocompromised Aboriginal adults exhibited significantly higher bactericidal antibody titers against Hia than did non-Aboriginal adults (p = 0.042 and 0.045 respectively), with no difference in functional antibody activity against Hib. IgM concentrations against Hia were higher than IgG in most study groups; the inverse was true for antibody concentrations against Hib. Our results indicate that Aboriginal adults possess substantial serum bactericidal activity against Hia that is mostly due to IgM antibodies. The presence of sustained IgM against Hia suggests recent Hia exposure.

Transcriptional adaptation of pneumococci and human pharyngeal cells in the presence of a virus infection.

BACKGROUND: Viral upper respiratory tract infections are associated with increased colonization by Streptococcus pneumoniae but the mechanisms underlying this relationship are unclear. The objective of this study is to describe a comprehensive picture of the cellular interaction between the adhering bacteria and host cells in the presence or absence of a viral co-infection. RESULTS: Gene expression profiles of Detroit-562 pharyngeal cells, which were either mock-infected or infected with human respiratory syncytial virus (RSV) or human parainfluenza virus 3 (HPIV3), were analyzed using human microarrays. Transcription response of S. pneumoniae strain TIGR4 (serotype 4) in the presence of either mock- or viral-infected cells was analyzed by pneumococcal microarray. Significantly regulated genes were identified by both significance analysis of microarray (SAM) and a ≥ 2-fold change ratio cut-off. The adherence of S. pneumoniae to human pharyngeal cells was significantly augmented in the presence of RSV or HPIV3 infection. Global gene expression profiling of the host cells during infection with RSV or HPIV3 revealed increased transcription of carcinoembryonic antigen-related cell adhesion molecules (CEACAM1), CD47, fibronectin, interferon-stimulated genes and many other host cell adhesion molecules. Pneumococci increased transcription of several genes involved in adhesive functions (psaA, pilus islet), choline uptake and incorporation (lic operon), as well as transport and binding. CONCLUSIONS: We have identified a core transcriptome that represents the basic machinery required for adherence of pneumococci to D562 cells infected or not infected with a virus. These bacterial genes and cell adhesion molecules can potentially be used to control pneumococcal adherence occurring secondary to a viral infection.

Phenotypic, genomic, and transcriptional characterization of Streptococcus pneumoniae interacting with human pharyngeal cells.

BACKGROUND: Streptococcus pneumoniae is a leading cause of childhood morbidity and mortality worldwide, despite the availability of effective pneumococcal vaccines. Understanding the molecular interactions between the bacterium and the host will contribute to the control and prevention of pneumococcal disease. RESULTS: We used a combination of adherence assays, mutagenesis and functional genomics to identify novel factors involved in adherence. By contrasting these processes in two pneumococcal strains, TIGR4 and G54, we showed that adherence and invasion capacities vary markedly by strain. Electron microscopy showed more adherent bacteria in association with membranous pseudopodia in the TIGR4 strain. Operons for cell wall phosphorylcholine incorporation (lic), manganese transport (psa) and phosphate utilization (phn) were up-regulated in both strains on exposure to epithelial cells. Pneumolysin, pili, stress protection genes (adhC-czcD) and genes of the type II fatty acid synthesis pathway were highly expressed in the naturally more invasive strain, TIGR4. Deletion mutagenesis of five gene regions identified as regulated in this study revealed attenuation in adherence. Most strikingly, ∆SP_1922 which was predicted to contain a B-cell epitope and revealed significant attenuation in adherence, appeared to be expressed as a part of an operon that includes the gene encoding the cytoplasmic pore-forming toxin and vaccine candidate, pneumolysin. CONCLUSION: This work identifies a list of novel potential pneumococcal adherence determinants.

A Policy Analysis of Preparedness for Hurricane Evacuations in the United States, 1990 to 2019: Implementation in Coastal States.

Hurricane or typhoon evacuations in the United States are typically managed by state, territorial, or tribal emergency management officials with federal, state, and local agency operational support. The evacuation process may involve issuing mandatory or "voluntary" evacuation orders to alert the community and mitigate loss of life and injury. We conducted an analysis of state and local hurricane evacuation policies identified through a literature review (January 1990 to June 2019) and key informant interviews with state public health and emergency management officials in Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, and Texas in October and November 2019. Findings from the literature review show that most gaps in hurricane evacuation preparedness-based on 44 policy-related publications identified in the review-could be categorized into 4 themes: shelters, evacuation decisionmaking, at-risk populations, and transportation. Findings from key informant interviews for 7 states revealed that coastal states have been able to address most of these gaps since Hurricane Katrina in 2005. However, an important remaining gap in preparedness is providing timely warnings to at-risk populations during hurricane evacuations.

Revaccination with a 23-valent pneumococcal polysaccharide vaccine induces elevated and persistent functional antibody responses in adults aged 65 > or = years.

BACKGROUND: Older adults are at high risk of developing invasive pneumococcal disease, but the optimal timing and number of vaccine doses needed to prevent disease among this group are unknown. We compared revaccination with 23-valent pneumococcal polysaccharide vaccine (PN23) with primary vaccination for eliciting initial and persistent functional antibody responses. METHODS: Subjects aged > or = 65 years were enrolled. Functional (opsonic) and total immunoglobulin (Ig) G antibody levels were measured following either PN23 primary vaccination (n = 60) or revaccination 3-5 years after receiving a first PN23 vaccination (n = 60). Antibody against vaccine serotypes 4, 14, and 23F was measured at prevaccination (day 0), 30 days after vaccination, and 5 years after vaccination. RESULTS: By day 30, both primary vaccination and revaccination induced significant increases in opsonic and IgG antibody levels. Day 30 levels following revaccination were slightly lower but not significantly different than those after primary vaccination. Year 5 levels were similar in both groups and remained significantly higher than prevaccination levels for primary vaccination subjects. There was good agreement between postvaccination opsonic and IgG antibody levels. CONCLUSIONS: Revaccination of older adults with PN23 was comparable to primary vaccination for inducing elevated and persistent functional and IgG antibody responses.

An Innovative United States-Mexico Community Outreach Initiative for Hispanic and Latino People in the United States: A Collaborative Public Health Network.

Collaborative partnerships are a useful approach to improve health conditions of disadvantaged populations. The Ventanillas de Salud (VDS) ("Health Windows") and Mobile Health Units (MHUs) are a collaborative initiative of the Mexican government and US public health organizations that use mechanisms such as health fairs and mobile clinics to provide health information, screenings, preventive measures (eg, vaccines), and health services to Mexican people, other Hispanic people, and underserved populations (eg, American Indian/Alaska Native people, geographically isolated people, uninsured people) across the United States. From 2013 through 2019, the VDS served 10.5 million people (an average of 1.5 million people per year) at Mexican consulates in the United States, and MHUs served 115 461 people from 2016 through 2019. We describe 3 community outreach projects and their impact on improving the health of Hispanic people in the United States. The first project is an ongoing collaboration between VDS and the Centers for Disease Control and Prevention (CDC) to address occupational health inequities among Hispanic people. The second project was a collaboration between VDS and CDC to provide Hispanic people with information about Zika virus infection and health education. The third project is a collaboration between MHUs and the University of Arizona to provide basic health services to Hispanic communities in Pima and Maricopa counties, Arizona. The VDS/MHU model uses a collaborative approach that should be further assessed to better understand its impact on both the US-born and non-US-born Hispanic population and the public at large in locations where it is implemented.

Evolution of the Public Health Preparedness and Response Capability Standards to Support Public Health Emergency Management Practices and Processes.

In spring 2011, the Centers for Disease Control and Prevention (CDC) released Public Health Preparedness Capabilities: National Standards for State and Local Planning. The capability standards provide a framework that supports state, local, tribal, and territorial public health agency preparedness planning and response to public health threats and emergencies. In 2017, a project team at the CDC Division of State and Local Readiness incorporated input from subject matter experts, national partners, and stakeholders to update the 2011 capability standards. As a result, CDC released the updated capability standards in October 2018, which were amended in January 2019. The original structure of the 15 capability standards remained unchanged, but updates were made to capability functions, tasks, and resource elements to reflect advances in public health emergency preparedness and response practices since 2011. When the number of functions and tasks in the 2018 capability standards were compared to those in the 2011 capabilities, only 20% (3/15) of the capabilities had a decrease in function number. The majority of changes were at the task level (task numbers changed in 80%, or 12/15, capabilities) in the 2018 version. The capability standards provide public health agencies with a practical framework, informed by updated science and tools, which can guide prioritization of limited resources to strengthen public health agency emergency preparedness and response capacities.

An in vitro model to assess pneumococcal adherence to nasopharyngeal cells under competition conditions.

Pneumococcal conjugate vaccine (PCV7) reduces invasive disease and carriage caused by vaccine serotypes (VS). An increase in carriage and disease with non-vaccine serotypes (NVS) has been observed. We have developed an in vitro model with human nasopharyngeal (NP) epithelial cells (Detroit 562) to assess the adherence capacity of Streptococcus pneumoniae to NP cells in the presence or absence of a competing Pnc strain. Two hundred and fifty pneumococcal (Pnc) strains (10 strains per serotype for 7 VS and 18 NVS) were tested for their opacity phenotype. Strains exhibiting (> or =50%) the transparent phenotype (n=72) were evaluated for their adherence capacity to Detroit 562 cells. Mean adherence capacity (> or =129 CFU/well) to NP cells was high for VS 18C, 4, and 9V and for NVS 16F, 10A, and 6A. In the in vitro competition experiments, VS strains out-competed (42/108) or co-existed (43/108) with NVS strains for adherence to NP cells in most co-inoculations. By contrast, NVS (15C, 16F, 31, and 35B) out-competed with VS in only 9 of 108 co-inoculations. Serotype 16F out-competed or co-existed with some VS and NVS strains. This model may be used to identify Pnc strains of a given serotype with competitive potentials for replacement of VS in the nasopharynx and to screen Pnc strains for animal colonization models.

Immune Responses in U.S. Military Personnel Who Received Meningococcal Conjugate Vaccine (MenACWY) Concomitantly with Other Vaccines Were Higher than in Personnel Who Received MenACWY Alone.

Immunological responses to vaccination can differ depending on whether the vaccine is given alone or with other vaccines. This study was a retrospective evaluation of the immunogenicity of a tetravalent meningococcal conjugate vaccine for serogroups A, C, W, and Y (MenACWY) administered alone (n = 41) or concomitantly with other vaccines (n = 279) to U.S. military personnel (mean age, 21.6 years) entering the military between 2006 and 2008. Concomitant vaccines included tetanus/diphtheria (Td), inactivated polio vaccine (IPV), hepatitis vaccines, and various influenza vaccines, among others; two vaccine groups excluded Tdap and IPV. Immune responses were evaluated in baseline and postvaccination sera for Neisseria meningitidis serogroups C and Y 1 to 12 months (mean, 4.96 months) following vaccination. Functional antibodies were measured by using a serum bactericidal antibody assay with rabbit complement (rSBA) and by measurement of serogroup-specific immunoglobulin G (IgG) antibodies. The percentage of vaccinees reaching threshold levels (IgG concentration in serum, ≥2 µg/ml; rSBA titer, ≥8) corresponding to an immunologic response was higher postvaccination than at baseline (P < 0.001). Administration of MenACWY along with other vaccines was associated with higher geometric means of IgG concentrations and rSBA titers than those measured 4.60 months after a single dose of MenACWY. In addition, higher percentages of vaccinees reached the immunological threshold (range of odds ratios [ORs], 1.5 to 21.7) and more of them seroconverted (OR range, 1.8 to 4.8) when MenACWY was administered with any other vaccine than when administered alone. Additional prospective randomized clinical trials are needed to confirm the observed differences among groups in the immune response to MenACWY when given concomitantly with other vaccines to U.S. military personnel.

No evidence of a mild form of inhalational Bacillus anthracis infection during a bioterrorism-related inhalational anthrax outbreak in Washington, D.C., in 2001.

BACKGROUND: The mail-related dispersal of Bacillus anthracis spores in the Washington, D.C., area during October 2001 resulted in 5 confirmed cases of inhalational anthrax. We identified an additional 144 ill persons who were potentially exposed to aerosolized spores and whose symptoms were compatible with early inhalational anthrax but whose clinical course and nonserologic laboratory evaluation revealed no evidence for B. anthracis infection. We hypothesized that early antibiotic use could have decreased the sensitivity of diagnostic tests or that bioterrorism-related inhalational anthrax may include mild disease. METHODS: Eligible patients included those with illness compatible with early inhalational anthrax who had potential exposure to B. anthracis. Patient serum samples were tested for immunoglobulin G (IgG) antibody against B. anthracis protective antigen (PA) using a sensitive enzyme-linked immunosorbant assay (sensitivity, 97.6%). RESULTS: Of the 144 eligible patients, 66 (46%) had convalescent-phase serum samples available for testing; 29 (44%) worked in an area considered to pose a high risk of exposure to B. anthracis spores. Of the 37 patients who worked in areas that did not meet the definition of high-risk exposure, 23 (62%) worked in United States postal or other government facilities in which exposure was plausible but not documented. None of the 66 patients with convalescent-phase serum samples showed evidence of an anti-PA IgG serologic response to B. anthracis. CONCLUSIONS: These data suggest that a mild form of inhalational anthrax did not occur and that surveillance for moderate or severe illness was adequate to identify all inhalational anthrax cases resulting from the Washington, D.C., bioterrorism-related anthrax exposures.

Immune response to pneumococcal polysaccharides 4 and 14 in elderly and young adults. I. Antibody concentrations, avidity and functional activity.

Streptococcus pneumoniae is a serious worldwide pathogen and the focus of numerous vaccine development projects. Currently the most widely accepted surrogate marker for evaluating the efficacy of a given vaccine is to utilize ELISA. Measurement of antibody concentration by ELISA without reduction in cross-reactive antibodies causes an overestimation of antibody concentration and therefore protection, this is most notable in the aged, an at risk group for this infection. We compared the immune response to the pneumococcal polysaccharides (PPS) 4 and 14 of 20 young to 20 elderly adults. Pre-and post-vaccination IgG antibody concentrations and antibody avidity against PPS4 and PPS14 were measured using two different enzyme-linked immunosorbant assay (ELISA) absorption protocols. All sera were pre-absorbed with either cell-wall polysaccharide (CPS), or CPS and serotype 22F polysaccharide. Pre- and post-vaccination IgG antibody concentrations for serotype 4, but not 14, were significantly lowered with the additional absorption with serotype 22F polysaccharide in both age groups. Young and elderly demonstrated a significant increase from pre- to post-immunization antibody concentration, using either absorption method; and opsonophagocytic antibody titers in response to both PPS4 and PPS14. The correlation coefficients between ELISA and opsonophagocytic assays were improved by additional absorption with serotype 22F in response to serotype 4, but not serotype 14 in all age groups. Opsonophagocytic antibody titers in a sub-group of elderly (>77 years of age) were significantly lower than the opsonophagocytic antibody concentrations in young adults. These results suggest the importance of eliminating cross-reactive antibodies from ELISA measurements by absorption of serum and an age-related impairment in the antibody response to pneumococcal polysaccharides.

Effect of multiple, simultaneous vaccines on polio seroresponse and associated health outcomes.

BACKGROUND: Administration of multiple simultaneous vaccines to infants, children, and military recruits is not uncommon. However, little research exists to examine associated serological and health effects, especially in adults. METHOD: We retrospectively examined 416 paired serum specimens from U.S. military subjects who had received the inactivated polio vaccine (IPV) alone or in combination with either 1 other vaccine (<3 group) or 4 other vaccines (>4 group). Each of the 2 groups was subdivided into 2 subgroups in which Tdap was present or absent. RESULTS: The >4 group was associated with a higher proportion of polio seroconversions than the <3 group (95% vs. 58%, respectively, p<0.01). Analysis of the <3 subgroup that excluded Tdap vs. the >4 subgroup that excluded Tdap showed no difference between them (p>0.1). However, the >4 subgroup that included Tdap had significantly more seroconversions than either the <3 subgroup that excluded Tdap or the >4 subgroup that excluded Tdap (p<0.01). Overall, at least 98% of subjects were at or above the putative level of seroprotection both pre- and post-vaccination, yet at least 81% of subjects seroconverted. In an analysis of 400 of the subjects in which clinic in- and outpatient encounters were counted over the course of 1 year following vaccinations, there was no significant difference between the 2 groups (p>0.1). CONCLUSION: A combination of >4 vaccines including IPV appeared to have an immunopotentiation effect on polio seroconversion, and Tdap in particular was a strong candidate for an important role. The dose of IPV we studied in our subjects, who already had a high level of seroprotection, acted as a booster. In addition, there appear to be no negative health consequences from receiving few versus more multiple simultaneous vaccinations.

Persistence of serogroup C antibody responses following quadrivalent meningococcal conjugate vaccination in United States military personnel.

Serogroup C meningococcal (MenC) disease accounts for one-third of all meningococcal cases and causes meningococcal outbreaks in the U.S. Quadrivalent meningococcal vaccine conjugated to diphtheria toxoid (MenACYWD) was recommended in 2005 for adolescents and high risk groups such as military recruits. We evaluated anti-MenC antibody persistence in U.S. military personnel vaccinated with either MenACYWD or meningococcal polysaccharide vaccine (MPSV4). Twelve hundred subjects vaccinated with MenACYWD from 2006 to 2008 or MPSV4 from 2002 to 2004 were randomly selected from the Defense Medical Surveillance System. Baseline serologic responses to MenC were assessed in all subjects; 100 subjects per vaccine group were tested during one of the following six post-vaccination time-points: 5-7, 11-13, 17-19, 23-25, 29-31, or 35-37 months. Anti-MenC geometric mean titers (GMT) were measured by rabbit complement serum bactericidal assay (rSBA) and geometric mean concentrations (GMC) by enzyme-linked immunosorbent assay (ELISA). Continuous variables were compared using the Wilcoxon rank sum test and the proportion of subjects with an rSBA titer ≥ 8 by chi-square. Pre-vaccination rSBA GMT was <8 for the MenACWYD group. rSBA GMT increased to 703 at 5-7 months post-vaccination and decreased by 94% to 43 at 3 years post-vaccination. GMT was significantly lower in the MenACWYD group at 5-7 months post-vaccination compared to the MPSV4 group. The percentage of MenACWYD recipients achieving an rSBA titer of ≥ 8 decreased from 87% at 5-7 months to 54% at 3 years. There were no significant differences between vaccine groups in the proportion of subjects with a titer of ≥ 8 at any time-point. GMC for the MenACWYD group was 0.14 µg/mL at baseline, 1.07 µg/mL at 5-7 months, and 0.66 µg/mL at 3 years, and significantly lower than the MPSV4 group at all time-points. Anti-MenC responses wane following vaccination with MenACYWD; a booster dose is needed to maintain protective levels of circulating antibody.

Absence of high molecular weight proteins 1 and/or 2 is associated with decreased adherence among non-typeable Haemophilus influenzae clinical isolates.

High molecular weight (Hmw) proteins 1 and 2, type IV pilin protein (PilA), outer-membrane protein P5 (OmpP5), Haemophilus protein D (Hpd) and Haemophilus adhesive protein (Hap) are surface proteins involved in the adherence of non-typeable Haemophilus influenzae. One hundred clinical isolates were evaluated for the presence of the genes encoding these proteins by PCR and for their adherence capacity (AC) to Detroit 562 nasopharyngeal cells (D562). The majority of isolates were from blood (77/100); other sites were also represented. Confluent D562 monolayers (1.2×10(5) cells per well) were inoculated with standardized minimal infective doses (m.o.i.) of 10(2), 10(3) or 10(4) c.f.u. per well. The AC was categorized as low (<10 %) or high (≥10 %) depending on the percentage of c.f.u. adhering per well. All the isolates evaluated showed adherence: 69/100 (69 %) demonstrated high adherence, while 31/100 (31 %) showed low adherence. Of all the genes evaluated, hmw1A and/or hmw2A were detected in 69/100 (69 %) of isolates. The presence of hmw1A and/or hmw2A was associated with increased adherence to D562 cells (P≤0.001). Dot immunoblots were performed to detect protein expression using mAbs 3D6, AD6 and 10C5. Among the high-adherence isolates (n = 69), 72 % reacted with 3D6 and 21 % with 10C5. Our data indicate that the absence of Hmw1 and/or Hmw2 was associated with decreased adherence to D562 cells.

Measurement of Haemophilus influenzae type a capsular polysaccharide antibodies in cord blood sera.

We measured anti-Haemophilus influenzae type a capsular polysaccharide serum immunoglobulin G antibodies in cord blood sera from Mexican (n = 68) and Chilean mothers (n = 72) by enzyme-linked immunosorbent assay. Measurable antibodies were found in 79.3% of samples. Immunoglobulin G antibodies correlated with serum bactericidal activity (r = 0.66). This enzyme-linked immunosorbent assay can be used for the evaluation of adaptive immune responses to Haemophilus influenzae type a and serosurveillance studies in populations at risk.