Fourfold Increase In Titer Research Articles

Antibody response after feline panleukopenia virus vaccination in kittens with and without intestinal parasites.

Vaccinations should only be given to healthy cats, and deworming before vaccination is generally recommended; however, so far, no study has investigated the influence of intestinal parasitic infection on the immune response in kittens. The aim of this prospective study was to compare the antibody response to feline panleukopenia virus (FPV) vaccination in kittens with and without intestinal parasites. Overall, 74 healthy kittens were included. Of these, 17 had intestinal parasites (12/17 Toxocara cati, 6/17 Cystoisospora felis, 1/17 Capillaria species). Both kittens with and without (n = 57) parasites received two primary kitten vaccinations with modified live FPV vaccines in a 4-week interval starting at the age of 8-12 weeks. Anti-FPV antibodies were determined at the beginning of the study (week 0) and at week 8 (4 weeks after the second vaccination) by haemagglutination inhibition. A ⩾four-fold titre increase (week 8 vs week 0) was defined as a response to vaccination. Comparison of the immune response in the kittens with and without intestinal parasites was performed using Pearson's χ2 test. Pre-vaccination antibodies were present in 4/17 (23.5%) kittens with intestinal parasites and in 24/57 (42.1%) without parasites. A ⩾four-fold titre increase was seen in 13/17 (76.5%) kittens with parasites compared with 32/57 (56.1%) kittens without parasites. There was neither a significant difference in pre-vaccination antibodies (P = 0.17), nor in vaccination response (P = 0.13) between kittens with and without parasites. The results indicate that asymptomatic intestinal infections with endoparasites do not interfere with the immune response to kitten vaccination series. Parasitic infection (at least with T cati, C felis and Capillaria species) is therefore not a reason to postpone important vaccinations.

Dietary Supplementation with Nucleotides, Short-Chain Fructooligosaccharides, Xylooligosaccharides, Beta-Carotene and Vitamin E Influences Immune Function in Kittens

Nucleotides, short-chain fructooligosaccharides (scFOS), xylooligosaccharides (XOS), β-carotene and vitamin E are reported to enhance immune function; however, the evidence of this in cats is limited. The aim of this study was to determine the immunomodulatory effects of these ingredients in kittens. Forty domestic short hair kittens were designated in litters to control or test diet for 28 weeks. Test diet was fortified with 0.33 g nucleotides, 0.45 g scFOS, 0.3 g XOS, 0.7 mg β-carotene and 66.5 mg vitamin E per 100 g diet. Kittens were vaccinated against feline parvovirus (FPV) and herpesvirus (FHV) at 10, 14 and 18 weeks. Kittens remained healthy, with no measured evidence of adverse health. Serum FPV and FHV antibody titres were significantly (p < 0.05) higher in the test diet group at week 23 and 27, respectively. A significantly (p < 0.05) higher proportion of test diet group kittens demonstrated an adequate response (four-fold titre increase) to FHV vaccination and a significantly (p < 0.05) higher proportion reached a protective antibody titre for FHV. Serum IgM was significantly (p < 0.05) higher in the test diet group. The test diet group demonstrated a stronger humoral immune response to vaccination, suggesting the diet supports immune defence, enabling a greater response to immune challenges.

Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthy adults aged 60 years and older: a randomised, double-blind, placebo-controlled, phase 1/2 clinical trial

BackgroundA vaccine against COVID-19 is urgently needed for older adults, in whom morbidity and mortality due to the disease are increased. We aimed to assess the safety, tolerability, and immunogenicity of a candidate COVID-19 vaccine, CoronaVac, containing inactivated SARS-CoV-2, in adults aged 60 years and older.MethodsWe did a randomised, double-blind, placebo-controlled, phase 1/2 clinical trial of CoronaVac in healthy adults aged 60 years and older in Renqiu (Hebei, China). Vaccine or placebo was given by intramuscular injection in two doses (days 0 and 28). Phase 1 comprised a dose-escalation study, in which participants were allocated to two blocks: block 1 (3 μg inactivated virus in 0·5 mL of aluminium hydroxide solution per injection) and block 2 (6 μg per injection). Within each block, participants were randomly assigned (2:1) using block randomisation to receive CoronaVac or placebo (aluminium hydroxide solution only). In phase 2, participants were randomly assigned (2:2:2:1) using block randomisation to receive either CoronaVac at 1·5 μg, 3 μg, or 6 μg per dose, or placebo. All participants, investigators, and laboratory staff were masked to treatment allocation. The primary safety endpoint was adverse reactions within 28 days after each injection in all participants who received at least one dose. The primary immunogenicity endpoint was seroconversion rate at 28 days after the second injection (which was assessed in all participants who had received the two doses of vaccine according to their random assignment, had antibody results available, and did not violate the trial protocol). Seroconversion was defined as a change from seronegative at baseline to seropositive for neutralising antibodies to live SARS-CoV-2 (positive cutoff titre 1/8), or a four-fold titre increase if the participant was seropositive at baseline. This study is ongoing and is registered with ClinicalTrials.gov (NCT04383574).FindingsBetween May 22 and June 1, 2020, 72 participants (24 in each intervention group and 24 in the placebo group; mean age 65·8 years [SD 4·8]) were enrolled in phase 1, and between June 12 and June 15, 2020, 350 participants were enrolled in phase 2 (100 in each intervention group and 50 in the placebo group; mean age 66·6 years [SD 4·7] in 349 participants). In the safety populations from both phases, any adverse reaction within 28 days after injection occurred in 20 (20%) of 100 participants in the 1·5 μg group, 25 (20%) of 125 in the 3 μg group, 27 (22%) of 123 in the 6 μg group, and 15 (21%) of 73 in the placebo group. All adverse reactions were mild or moderate in severity and injection site pain (39 [9%] of 421 participants) was the most frequently reported event. As of Aug 28, 2020, eight serious adverse events, considered unrelated to vaccination, have been reported by seven (2%) participants. In phase 1, seroconversion after the second dose was observed in 24 of 24 participants (100·0% [95% CI 85·8–100·0]) in the 3 μg group and 22 of 23 (95·7% [78·1–99·9]) in the 6 μg group. In phase 2, seroconversion was seen in 88 of 97 participants in the 1·5 μg group (90·7% [83·1–95·7]), 96 of 98 in the 3 μg group (98·0% [92·8–99·8]), and 97 of 98 (99·0% [94·5–100·0]) in the 6 μg group. There were no detectable antibody responses in the placebo groups.InterpretationCoronaVac is safe and well tolerated in older adults. Neutralising antibody titres induced by the 3 μg dose were similar to those of the 6 μg dose, and higher than those of the 1·5 μg dose, supporting the use of the 3 μg dose CoronaVac in phase 3 trials to assess protection against COVID-19.FundingChinese National Key Research and Development Program and Beijing Science and Technology Program.

Antibody response to feline herpesvirus-1 vaccination in healthy adult cats.

Vaccination against feline herpesvirus-1 (FHV-1) is recommended for all cats. However, it is unknown how adult healthy cats with different pre-vaccination antibodies respond to FHV-1 vaccination in the field. The aim of the study was to determine the prevalence of neutralising antibodies against FHV-1 in healthy adult cats and the response to FHV-1 vaccination within 28 days of vaccination. One hundred and ten cats (⩾1 year of age) that had not received a vaccination within the past 12 months were vaccinated with a combined FHV-1 vaccine. Antibodies against FHV-1 were determined before vaccination (day 0), on day 7 and day 28 by serum neutralisation test. Uni- and multivariate statistical analyses were used to determine factors associated with the presence of pre-vaccination antibodies and response to vaccination. Pre-vaccination neutralising antibody titres (⩾10) were present in 40.9% of cats (45/110; 95% confidence interval [CI] 32.2-50.3); titres were generally low (range 10-640). Antibody response to vaccination (⩾four-fold titre increase) was observed in 8.3% (9/109; 95% CI 4.2-15.1). Cats ⩾2 years of age were more likely to have pre-vaccination neutralising antibodies than cats aged between 1 and 2 years (odds ratio [OR] 24.619; P = 0.005). Cats from breeders were more likely to have pre-vaccination neutralising antibodies than privately owned cats (OR 7.070; P = 0.007). Domestic shorthair cats were more likely to have an at least four-fold titre increase vs purebred cats (OR 11.22; P = 0.027). Many cats have no detectable neutralising antibodies against FHV-1 despite previous vaccinations and fail to develop a ⩾four-fold titre increase after vaccination. This is likely because older cats and cats with a higher FHV-1 exposure risk are more likely to get infected with FHV-1 and thus to have FHV-1 neutralizing antibodies. Purebred cats more often fail to develop a ⩾four-fold titre increase after vaccination.

Antibody response to feline panleukopenia virus vaccination in cats with asymptomatic retrovirus infections: a pilot study.

Currently, there are only a few studies on how immunocompromised cats, such as cats infected with feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), respond to vaccination. Therefore, this study measured feline panleukopenia virus (FPV) antibodies in retrovirus-infected cats within a period of 28 days after FPV vaccination, and compared the immune response to that of non-infected cats. Eight asymptomatic retrovirus-infected cats (four FeLV, four FIV), and non-infected age-matched control cats (n = 67) were vaccinated with a commercial FPV modified live virus (MLV). Pre- and post-vaccination antibody titres were measured by haemagglutination inhibition (HI) on days 0, 7 and 28. An HI titre ⩾1:40 was defined as protective. An adequate response to vaccination was defined as a four-fold titre increase or higher. Comparison of the immune response of retrovirus-infected and non-infected cats was performed. Pre-vaccination FPV antibody titres ⩾1:40 were present in 100% (n = 8/8; 95% confidence interval [CI] 62.8-100) of retrovirus-infected and in 77.6% (n = 52/67; 95% CI 66.2-86.0) of non-infected cats. An adequate response to vaccination (titre increase ⩾four-fold) was seen in 1/8 retrovirus-infected cats (12.5%; 95% CI 0.1-49.2) compared with 22/67 non-infected cats (32.8%; 95% CI 22.8-44.8). In cats with high pre-vaccination titres (⩾1:160), a four-fold titre increase or higher was observed in 1/8 retrovirus infected cats (12.5%; 95% CI 0.1-49.2) compared with 4/42 non-infected cats (9.5%; 95% CI 3.2-22.6). None of the eight retrovirus-infected cats developed illness or vaccination side effects after vaccination with MLV against FPV within the 28 days. There were no significant differences between groups: for pre-vaccination titres; for at least four-fold titre increases following vaccination in either all cats or the cats with high pre-vaccination titres; and concerning adverse effects. All retrovirus-infected asymptomatic cats had pre-vaccination FPV antibodies indicating protection against panleukopenia. Response of retrovirus-infected cats to vaccination was similar to the response of non-infected cats.

Antibody response to feline panleukopenia virus vaccination in healthy adult cats.

According to prior studies, between 25.0% and 92.8% of adult cats have antibodies against feline panleukopenia virus (FPV) and thus are likely protected against FPV infection. It is, however, unknown how healthy adult cats with different antibody titres react to FPV vaccination in the field. Therefore, the aim of the study was to measure antibody titres in healthy adult cats within a period of 28 days after vaccination against FPV and to evaluate factors that are associated with a lack of adequate response to vaccination. One hundred and twelve healthy adult cats were vaccinated with a vaccine against FPV, feline herpesvirus and feline calicivirus. Antibodies against FPV were determined before vaccination (day 0), on day 7 and day 28 after vaccination by haemagglutination inhibition (HI). A HI titre ⩾1:40 was defined as protective. An adequate response to vaccination was defined as a four-fold titre increase. Uni- and multivariate statistical analysis was used to determine factors associated with an adequate response. Pre-vaccination antibody titres of ⩾1:40 were present in 64.3% (72/112; 95% confidence interval [CI] 55.1-72.6). Only 47.3% (53/112; 95% CI 37.8-57.0) of cats had an adequate response to vaccination. Factors associated with an adequate response to vaccination were lack of previous vaccination (odds ratio [OR] 15.58; 95% CI 1.4-179.1; P = 0.035), lack of antibodies (⩾1:40) prior to vaccination (OR 23.10; 95% CI 5.4-98.8; P <0.001) and breed (domestic shorthair cats; OR 7.40; 95% CI 1.4-38.4; P = 0.017). As none of the cats with high pre-vaccination antibody titres (⩾1:160) had an at least four-fold increase in FPV antibody titres, measurement of antibodies rather than regular revaccinations should be performed. Thus, evaluation of FPV antibody titre in cats with previous vaccinations against FPV are recommended prior to revaccination.

Diagnosis of leptospirosis in dogs

Rapid confirmation of the diagnosis leptospirosis is important in order to apply appropriate treatment; in addition, infected dogs are a zoonotic risk. Culture and isolation of living leptospires from blood, urine, or tissues is considered the reference standard of diagnosis. However, sensitivity are low, and leptospires require weeks to months to grow. Therefore, diagnosis of leptospirosis is most commonly based on antibody testing or the detection of Leptospira spp. DNA by PCR. Microscopic agglutination test (MAT) is currently still the recommended confirmatory test for canine leptospirosis, despite its numerous limitations (e. g., negative results in early infection, positive results due to vaccine-associated antibodies). ELISA can differentiate between IgG and IgM antibodies and thus, discriminate current infections from previous vaccination or exposure. Point-of-care tests and in-house-PCR tests have recently been developed for use in private practice allowing easy and immediate diagnosis. However, only few data on sensitivity and specificity of these tests exist so far. A reliable diagnosis can only be established in case of a positive PCR result or a fourfold titre increase in MAT.

Incident Tick-Borne Infections in a Cohort of North Carolina Outdoor Workers.

Tick-borne diseases cause substantial morbidity throughout the United States, and North Carolina has a high incidence of spotted fever rickettsioses and ehrlichiosis, with sporadic cases of Lyme disease. The occupational risk of tick-borne infections among outdoor workers is high, particularly those working on publicly managed lands. This study identified incident tick-borne infections and examined seroconversion risk factors among a cohort of North Carolina outdoor workers. Workers from the North Carolina State Divisions of Forestry, Parks and Recreation, and Wildlife (n = 159) were followed for 2 years in a randomized controlled trial evaluating the effectiveness of long-lasting permethrin-impregnated clothing. Antibody titers against Rickettsia parkeri, Rickettsia rickettsii, "Rickettsia amblyommii," and Ehrlichia chaffeensis were measured at baseline (n = 130), after 1 year (n = 82), and after 2 years (n = 73). Titers against Borrelia burgdorferi were measured at baseline and after 2 years (n = 90). Baseline seroprevalence, defined as indirect immunofluorescence antibody titers of 1/128 or greater, was R. parkeri (24%), R. rickettsii (19%), "R. amblyommii" (12%), and E. chaffeensis (4%). Incident infection was defined as a fourfold increase in titer over a 1-year period. There were 40 total seroconversions to at least one pathogen, including R. parkeri (n = 19), "R. amblyommii" (n = 14), R. rickettsii (n = 9), and E. chaffeensis (n = 8). There were no subjects whose sera were reactive to B. burgdorferi C6 antigen. Thirty-eight of the 40 incident infections were subclinical. The overall risk of infection by any pathogen during the study period was 0.26, and the risk among the NC Division of Forest Resources workers was 1.73 times that of workers in other divisions (95% confidence interval [CI]: 1.02, 2.92). The risk of infection was lower in subjects wearing permethrin-impregnated clothing, but not significantly (risk ratio = 0.81; 95% CI: 0.47, 1.39). In summary, outdoor workers in North Carolina are at high risk of incident tick-borne infections, most of which appear to be asymptomatic.

SEROLOGICAL DIAGNOSIS OF MODERN CHOLERA USING LIPOSOMAL ENTEROTOXIC DIAGNOSTICUM IN COMPLEMENT FIXATION TEST

Abstract. The possibility of serological diagnosis of cholera using cholera enterotoxic diagnostics kit in complement fixation test to detect anti-enterotoxic antibodies in sera of patients with cholera caused by hybrid variants of the El Tor biovar has been demonstrated. In patients with mild course of cholera anti-enterotoxic antibodies were detected in titres 1:50 and 1:200 in paired sera obtained on the 7th and 14th days of disease, respectively (fourfold titre increase). In patients with the course of medium severity 32-fold titre increase was recorded from the titre 1:100 in serum obtained on the fifth day of disease till the titre 1:3200 — on the twelfth day of disease. Antibodies titers reached 1:1600 and 1:800 were revealed in two medium course patients (adult and infant of 10 months) on the sixth day of disease.

Immune response, antibody persistence, and safety of a single dose of the quadrivalent meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine in adolescents and adults: results of an open, randomised, controlled study

BackgroundThe best strategy to protect individuals against meningococcal disease is to immunize against multiple serogroups. Immunogenicity, antibody persistence, and safety of the EU-licensed meningococcal ACWY-tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in healthy participants aged 11–55 years from the Philippines and Saudi Arabia.MethodsIn this phase IIb, open, controlled study, 500 participants were randomised (3:1) to receive one dose of MenACWY-TT or a licensed meningococcal polysaccharide vaccine (Men-PS). Functional antibody responses against meningococcal serogroups A, C, W-135, and Y were assessed by a serum bactericidal antibody assay using rabbit complement (rSBA) at Month 0, Month 1, Year 1, Year 2, and Year 3. Vaccine response was defined as an rSBA titre ≥32 at Month 1 in participants who were seronegative (rSBA titre <8) pre-vaccination and as at least a four-fold increase in titre in participants who were seropositive pre-vaccination. Solicited symptoms were recorded up to Day 4, safety outcomes up to Month 6, and serious adverse events related to vaccination up to Year 3.ResultsPre-specified criteria for non-inferiority of MenACWY-TT versus Men-PS were met in terms of rSBA vaccine response and incidence of grade 3 general symptoms. At Month 1, 82.7%–96.3% of MenACWY-TT and 69.7%–91.7% in Men-PS recipients had a vaccine response for each serogroup. At Year 3, ≥99.1% and ≥92.9% of MenACWY-TT recipients retained rSBA titres ≥8 and ≥128, respectively, as compared to ≥86.7% and ≥80.0% in the Men-PS group. Both vaccines had a clinically acceptable safety profile, although injection site redness and swelling were more frequent in MenACWY-TT recipients.ConclusionsThese results suggest that MenACWY-TT could protect adolescents and adults against meningococcal disease up to three years post-vaccination.Trial registrationThis study is registered at http://www.clinicaltrials.gov/NCT00356369.

Travel Medicine and Transplant Tourism in Solid Organ Transplantation

Travel Medicine and Transplant Tourism in Solid Organ Transplantation

Mediterranean Spotted Fever in Southeastern Romania

Although cases of Mediterranean spotted fever (MSF) have been reported for decades in southeastern Romania, there are few published data. We retrospectively studied 339 patients, diagnosed with MSF at the National Institute of Infectious Diseases “Prof. Dr. Matei Bals” between 2000 and 2011, in order to raise awareness about MSF in certain regions of Romania. According to the Raoult diagnostic criteria 171 (50.4%) had a score >25 points. Mean age was 52.5 years. One hundred and fifty-five (90.6%) patients were from Bucharest and the surrounding region. Almost all patients presented with fever (99.4%) and rash (98.2%), and 57.9% had evidence of a tick bite. There were no recorded deaths. Serologic diagnosis was made by indirect immunofluorescence assay. Of the 171 patients, serology results for R. conorii were available in 147. One hundred and twenty-three (83.7%) of them had a titer IgG ≥1 : 160 or a fourfold increase in titer in paired samples. MSF is endemic in southeastern Romania and should be considered in patients with fever and rash even in the absence of recognized tick exposure. Since the disease is prevalent in areas highly frequented by tourists, travel-associated MSF should be suspected in patients with characteristic symptoms returning from the endemic area.

Duration of serological response to canine parvovirus‐type 2, canine distemper virus, canine adenovirus type 1 and canine parainfluenza virus in client‐owned dogs inAustralia

To determine whether client-owned dogs in Australia, last vaccinated with Canvac(®) vaccines containing canine parvovirus-type 2 (CPV-2), canine distemper virus (CDV), canine adenovirus type 2 (CAV-2) ± canine parainfluenza virus (CPiV) at least 18 months ago, were seropositive or responded serologically to revaccination. A total of 235 dogs were recruited from 23 veterinary clinics, representing a variety of breeds, ages and time since last vaccination (TSLV: range 1.5-9 years, mean 2.8 years). Dogs had a blood sample taken and were revaccinated on day 0. A second blood sample was taken 7-14 days later. Blood samples were assessed for antibody titres to CPV-2 (by haemagglutination inhibition) and CDV, CAV type 1 (CAV-1) and CPiV (by virus neutralisation). Dogs with a day 0 titre >10 or a four-fold increase in titre following revaccination were considered to be serological responders. The overall percentage of dogs classified as serological responders was 98.7% for CPV-2, 96.6% for CDV, 99.6% for CAV-1 and 90.3% for CPiV. These results suggest that the duration of serological response induced by modified-live vaccines against CPV-2, CDV, CAV-1 and CPiV, including Canvac(®) vaccines, is beyond 18 months and may extend up to 9 years. Accordingly, these vaccines may be considered for use in extended revaccination interval protocols as recommended by current canine vaccine guidelines.

Rituximab-Treated Patients Have a Poor Response to Influenza Vaccination

The efficacy of influenza vaccination in patients treated with rituximab is a clinically important question. Rheumatology clinics are populated with patients receiving rituximab for a broad array of disorders. Although several studies have explored the efficacy of other vaccines in rituximab-treated populations, results have been conflicting. We wished to define influenza vaccine efficacy in a rituximab-treated cohort. We examined 17 evaluable subjects treated with rituximab for rheumatologic conditions. T cell subsets, B cells subsets, T cell function, and B cell function were evaluated at specific time points along with hemagglutinination inhibition titers after receiving the standard inactivated influenza vaccine. T cell subset counts were significantly different than controls but did not change with rituximab. B cells depleted in all patients but were in various stages of recovery at the time of vaccination. Influenza vaccine responsiveness was poor overall, with only 16 % of subjects having a four-fold increase in titer. Pre-existing titers were retained throughout the study, however. The ability to respond to the influenza vaccine appeared to be related to the degree of B cell recovery at the time of vaccination. This study emphasizes that antibody responses to vaccine are impaired in subjects treated with rituximab and supports the concept that B cell recovery influences influenza vaccine responsiveness.

Human Metapneumovirus

Human metapneumovirus (hMPV) is a common pathogen that can cause both upper and lower respiratory tract infections, particularly in children, elderly adults, and immunocompromised hosts. Since its initial identification in 2001, hMPV has been isolated from individuals with acute respiratory tract infections (ARTIs) in virtually every continent. Serological studies indicate that it has caused human infection since 1958 or earlier. The epidemiology and clinical manifestations of hMPV are similar to those of the human respiratory syncytial virus (hRSV). HMPV has a seasonal variation: it circulates in late winter to early spring in temperate climates; late spring and summer in tropical regions. In young children, symptoms range from mild upper respiratory tract infections to severe lower respiratory tract infections (eg, bronchiolitis, croup, and pneumonia). In adults, hMPV reinfection typically presents with colds and flulike clinical manifestations. The disease is more severe (sometimes lethal) in immunocompromised hosts. Reverse transcription polymerase chain reaction (RT-PCR) is the most sensitive test with which to detect hMPV infection. Direct detection of hMPV antigens with an immunofluorescent antibody test is available but is less sensitive than PCR. Antibody testing is used mainly for retrospective diagnosis (≥ fourfold increase in titer or seroconversion) and for epidemiological studies. The mainstay of treatment of hMPV infections is supportive. Ribavirin has similar activity in vitro and in animal models against hRSV and hMPV, but its efficacy in vivo is unproven. Monoclonal antibodies have activity in murine models but are not available in humans. Several vaccines are promising in animal models, but their safety and efficacy have not yet been evaluated in humans.

Reduced immunogenicity of influenza vaccines in HIV-infected compared with uninfected pregnant women is associated with regulatory T cells

To evaluate the immunogenicity of influenza vaccines in HIV-infected pregnant women and the factors that may determine this response. Prospective, single-site study of HIV-infected and uninfected women. Pregnant women had the following immunologic measurements at vaccination, 6 weeks after immunization, and 12 weeks after delivery: hemagglutination inhibition (HAI) antibody titers, lymphocyte proliferation (LPA), interferon-γ enzyme-linked immunospot (ELISPOT), and polychromatic flow cytometric enumeration of influenza-specific effector and regulatory T cells. At vaccination, demographic and gestational characteristics did not differ significantly between the 20 HIV-infected and 18 uninfected participants. Prevaccination HAI geometric mean titers (GMTs) against all strains of influenza in the vaccines were similar between the two groups. Antibody responses to vaccination measured by GMT or four-fold titer increase were significantly lower in HIV-infected compared with uninfected pregnant women for influenza A strains. Antibody responses to influenza B were equally low in the two groups of participants. There were no significant LPA or ELISPOT responses to vaccination in either group. LPA results were significantly lower in HIV-infected compared with uninfected women at all time points, but ELISPOT were not. Influenza-specific regulatory CD4(+)FoxP3(+)% and CD4(+)IL10(+)% increased after vaccination in both groups, but significantly more in HIV-infected compared with uninfected pregnant women. Higher influenza-specific CD4(+)FoxP3(+)% postvaccination correlated with lower antibody responses to the vaccine and lower LPA results. Influenza vaccines have reduced immunogenicity in HIV-infected compared with uninfected pregnant women. In HIV-infected women, increased regulatory CD4(+)FoxP3(+)% may attenuate the immunogenicity of vaccines.

Effect of 25‐hydroxyvitamin D status on serological response to influenza vaccine in prostate cancer patients

Epidemiologic data suggest that there is an association between vitamin D deficiency and influenza infection. We conducted a prospective influenza vaccination study to determine the influence of vitamin D status on serological response to influenza vaccine in prostate cancer (CaP) patients. During the 2006-2007 influenza season, CaP patients treated at Roswell Park Cancer Institute were offered vaccination with the trivalent influenza vaccine (Fluzone®, 2006-2007) and sera collected for hemagglutination inhibition (HI) assay titers before and 3 months after vaccination. Response to vaccination was defined as ≥1:40 titer ratio or a fourfold increase in titer at 3 months, against any of the three strains. Serum 25-hydroxyvitamin D (25-D₃) levels were measured using DiaSorin ¹²⁵I radioimmunoassay kits. Thirty-five patients with CaP participated in the study. Median baseline 25-D₃ level was 44.88 ng/ml (range: 9.16-71.98 ng/ml) Serological response against any of the three strains was noted in 80%. There was a significant effect of baseline 25-D3 level when tested as a continuous variable in relation to serological response (P = 0.0446). All patients in the upper quartile of 25-D3 level responded by mounting a serological response (P = 0.0344). None of the other baseline variables (age, race, chemotherapy status, or white cell count) had an effect on serological response. In this study in CaP patients, a replete vitamin D status was associated with more frequent serological response to influenza vaccine.

MF59-adjuvanted influenza vaccine confers superior immunogenicity in adult subjects (18–60 years of age) with chronic diseases who are at risk of post-influenza complications

The immunogenicity and reactogenicity of two influenza vaccines were evaluated in a randomised, double-blind trial in north-east Italy during winter 2005–2006. Of 238 adult subjects (18–60 years of age) with underlying chronic diseases, 120 received MF59-adjuvanted subunit vaccine (Sub/MF59) and 118 received conventional subunit vaccine (Subunit). At 4 weeks post-vaccination, geometric mean titres (GMT) were significantly ( P < 0.001) increased for both groups. For the A/H3N2 and B strains, significantly ( P < 0.02) higher GMT were reported for the Sub/MF59 group. The mean-fold increase in titre, the percentage of subjects with at least a four-fold titre increase and the seroprotection rate (≥1:40) were also higher in the Sub/MF59 group, with the seroprotection rate and four-fold titre increase achieving significance ( P = 0.002 and P = 0.02, respectively) for the A/H3N2 strain. Our results suggest that adults affected by chronic diseases can mount a satisfactory immune response to influenza vaccines, and that these vaccines are well tolerated. Addition of the MF59-adjuvant, however, enhances the immunogenicity of subunit influenza vaccine, conferring superior protection than a conventional subunit vaccine in this population, who are at high-risk of influenza-related complications.

Misclassification of the Stages of Syphilis: Implications for Surveillance

Syphilis cases were reviewed to see if reported stages met the Centers for Disease Control and Prevention case definition. Classification was excellent for primary and secondary and good for late latent, but half of early latent and unknown duration were misclassified. New surveillance definitions are suggested, comments requested. Uncertainty when staging latent syphilis should lead clinicians to call it late latent (requires more treatment) and disease investigators to call it early latent (priority for partner investigation). Accurate surveillance requires consistent case definitions. Assess validity of reported syphilis stages. Record reviews in 6 jurisdictions to determine if reported cases met the Centers for Disease Control and Prevention case definitions. Nine hundred seventy-three records from 6 jurisdictions in 2002 showed excellent agreement for reported primary (94.0%) and secondary (95.4%), good agreement for late latent (80.2%), and poor agreement for early latent (48.4%) and unknown duration (49.7%). Unknown duration (age < or =35 and nontreponemal test titer > or =32) was often misinterpreted to mean "not known." Early latent (within the past year, documented: seroconversion, fourfold titer increase, symptoms, or contact with an independently documented early syphilis case) was often misinterpreted to include patients with risky behavior, young age, or high nontreponemal test titers. The unknown duration stage should be dropped. Surveillance of latent syphilis would be more consistent if cases were reported as having high or low titers on nontreponemal test. Alternative approaches are solicited from readers.

Rapid detection of Mycoplasma pneumoniae IgM antibodies in pediatric patients using ImmunoCard Mycoplasma compared to conventional enzyme immunoassays

Mycoplasma pneumoniae is a common cause of community-acquired respiratory infection in children. An estimated 30% of Mycoplasma pneumoniae infections in those 5–15 years of age result in pneumonia and, overall, Mycoplasma pneumoniae is responsible for 10–40% of all cases of community-acquired pneumonia in children [1, 2]. A specific diagnosis of Mycoplasma pneumoniae infection is important since treatment with routinely used β-lactam antibiotics is ineffective against these organisms which lack a cell wall. Proper treatment of infected patients with macrolide antibiotics shortens the duration of overt infection and decreases the severity of respiratory symptoms [2, 3]. Unfortunately, the prompt and accurate diagnosis of Mycoplasma pneumoniae infection in children is hampered by the lack of standardized, rapid, and specific testing methods. Current methods for the specific diagnosis of Mycoplasma pneumoniae infection include culture, serology, and polymerase chain reaction (PCR). Serology has been the mainstay for the diagnosis ofMycoplasma pneumoniae infections, particularly since culture methods are insensitive, require specialized techniques, and at least 2–3 weeks for results [4]. PCR is a promising diagnostic tool for the identification of Mycoplasma pneumoniae in clinical specimens, but it is available only in specialized laboratories. No PCR kits approved by the Food and Drug Administration of the USA are yet available, and inhouse performance characteristics vary substantially among laboratories [3–5]. Results of several studies evaluating various serologic methods have been published, but an assessment of the actual performance of the tests is hampered by the lack of standardized, comparative methods [6–9]. Older methods have tested for complement fixing antibodies that measure predominantly immunoglobulin (Ig)G and usually peak 1– 3 weeks after the onset of infection. Because complement fixing antibodies can persist for several years after infection, it is necessary to obtain paired acute-phase and convalescent-phase sera to demonstrate seroconversion or a fourfold increase in titer for reliable diagnosis. The need for both specimens typically affords only a retrospective diagnosis of acute infection. Enzyme immunoassay (EIA) and indirect fluorescent antibody test methods may provide a more sensitive and specific diagnosis compared to the complement fixation test [8–10]. The Meridian ImmunoCard Mycoplasma IgM assay (Meridian Bioscience, Cincinnati, OH, USA) is a membrane-based, qualitative EIA in which patient sera is allowed to react with Mycoplasma pneumoniae antigen extracts impregnated on filter paper. It requires minimal hands-on time, no additional equipment, and includes an internal control. In the study reported here, the performance of the Meridian ImmunoCard Mycoplasma test was compared to two conventional microtiter plate EIAs for the detection of IgM antibodies to Mycoplasma pneumoniae using acute-phase serum samples from 145 pediatric patients. The average age of the patients was 7.1 years (range, 8 months–17 years) and 46% were female. Initially, all samples were assayed using the ImmunoCard Mycoplasma IgM assay (Meridian Bioscience) according to the manufacturer’s instructions. Samples were stored at −30°C, thawed once, and retrospectively analyzed using the ImmunoWELL Mycoplasma pneumoniae IgM EIA (GenBio, San Diego, CA, USA) as recommended by the manufacturer. A subset of samples with discrepant results between ImmunoCard and ImmunoWELL were tested by a third EIA method, the Zeus J. J. Dunn (*) . J. Evans Department of Pathology, Cook Children’s Medical Center, Fort Worth, TX, 76104, USA e-mail: jdunn@cookchildrens.org Tel.: +1-682-885-6475 Fax: +1-682-885-6111