Perinatal outcomes and serological results in neonates of pregnant women seropositive to SARS-CoV-2: A cross-sectional descriptive study

Introduction SARS-CoV-2 has spread rapidly throughout the world. However, its ability to cause severe disease is not homogeneous according to sex and the different age groups. Objective To determine perinatal characteristics, morbidity, mortality, and serological results in neonates from seropositive pregnant women to SARS-CoV2. Methods We did a retrospective, descriptive, cross-sectional study. We included all newborns from positive pregnant women to SARS-CoV-2, between April 15 and May 10, 2020, who delivered in the National Perinatal Maternal Institute of Peru. The study extracted maternal and neonatal variables collected from the medical charts. The data were analyzed using descriptive statistics and Fischer's exact test. Results One hundred fourteen neonates were identified, 36.8% IgM/IgG positive for SARS-CoV-2, 7% IgG, and 56.2% had negative serology. The obstetric complications were premature rupture of membranes (14.9%) and preterm birth (8,8%). 8.8% of newborns had an Apgar score of less than or equal to six minutes, and of those, only one persisted after five minutes; three newborns died. There was an association between the type of maternal immunoglobulin and the serology of the newborn (p < 0.05). No association was observed between perinatal results and maternal immunoglobulin type (p > 0.05) or serological results in the newborn for SARS-CoV-2 (p > 0.05). Conclusion 43.9% of seropositive mothers' neonates to SARS-CoV-2 had a positive serological result, more frequently type IgM/IgG. 10.5% of the neonates had some morbidity, more frequent prematurity, low birth weight, and 2.6% died. Perinatal results were not associated with the type of immunoglobulin of mothers seropositive to SARS CoV-2; similarly, perinatal results were not associated with serological results in the newborn

Self-reported patient history to assess hepatitis B virus serological status during a large screening campaign

When assessing hepatitis B virus (HBV) status in clinical settings, it is unclear whether self-reports on vaccination history and previous HBV-test results have any diagnostic capacity. Of 3997 participants in a multi-centre HBV-screening study in Paris, France, 1090 were asked questions on their last HBV-test result and vaccination history. Discordance between self-reported history compared with infection status (determined by serology) was calculated for participants claiming ‘negative’, ‘effective vaccine’, ‘past infection’, or ‘chronic infection’ HBV-status. Serological testing revealed that 320 (29.4%) were non-immunised, 576 (52.8%) were vaccinated, 173 (15.9%) had resolved the infection and 21 (1.9%) were hepatitis B surface antigen positive. In total 208/426 (48.8%) participants with a self-reported history of ‘negative’ infection had a discordant serological result, in whom 128 (61.5%) were vaccinated and 74 (35.6%) had resolved infections. A total of 153/599 (25.5%) participants self-reporting ‘effective vaccine’ had a discordant serological result, in whom 100 (65.4%) were non-immunised and 50 (32.7%) were resolved infections. Discordance for declaring ‘past’ or ‘chronic infection’ occurred in 9/55 (16.4%) and 3/10 (30.0%) individuals, respectively. In conclusion, self-reported HBV-status based on participant history is partially inadequate for determining serological HBV-status, especially between negative/vaccinated individuals. More adapted patient education about HBV-status might be helpful for certain key populations.

An outbreak of chickenpox in an asylum seeker centre in Italy: outbreak investigation and validity of reported chickenpox history, December 2015–May 2016

An outbreak of chickenpox occurred between December 2015 and May 2016 among asylum seekers in a reception centre in Latium, Italy. We describe the epidemiological and laboratory investigations, control measures and validity of reported history of chickenpox infection. Serological screening of all residents and incoming asylum seekers was performed, followed by vaccine offer to all susceptible individuals without contraindication. Forty-six cases were found and 41 were associated with the outbreak. No complications, hospitalisations or deaths occurred. Serological testing was performed in 1,278 individuals and 169 were found to be susceptible, with a seroprevalence of 86.8%. A questionnaire was administered to 336 individuals consecutively attending the CARA health post to collect their serological result. The sensitivity, specificity and the positive and negative predictive value (PPV and NPV) of the reported history of chickenpox were 45.0%, 76.1%, 88.3% and 25.6%, respectively. We observed an increasing trend for the PPV and decreasing trend for the NPV with increasing age. Our report confirms that, in the asylum seeker population, chickenpox history is not the optimal method to identify susceptible individuals. Our experience supports the need for additional prevention and control measures and highlights the importance of national and local surveillance systems for reception centres.

Serological and infection statuses of dogs from a visceral leishmaniasis-endemic area

OBJECTIVE This study investigated the serological status of dogs living in a visceral leishmaniasis-endemic area and its correlation with the parasitological condition of the animals.METHODS Canine humoral response was evaluated using the sera of 134 dogs by enzyme-linked immunosorbent assay and immunohistochemistry to detect parasites in the skin, lymph node, and spleen of the animals. The specific antibodies investigated were IgG, IgG1, IgG2, and IgE.RESULTS According to the parasitological, laboratory, and clinical findings, the dogs were placed into one of four groups: asymptomatic with (AP+, n = 21) or without (AP-, n = 36) Leishmania tissue parasitism and symptomatic with (SP+, n = 52) or without (SP-, n = 25) parasitism. Higher IgG and IgE levels were positively correlated with the infection condition and parasite load, but not with the clinical status. In all groups, total IgG was the predominant antibody, which occurred at the expense of IgG2 instead of IgG1. Most of the infected dogs tested positive for IgG (SP+, 98.1%; AP+, 95.2%), whereas this was not observed with IgE (SP+, 80.8%; AP+, 71.2%). The most relevant finding was the high positivity of the uninfected dogs for Leishmania-specific IgG (SP-, 60.0%; AP-, 44.4%), IgE (SP-, 44.0%; AP-, 27.8%), IgG1 (SP-, 28.0%; AP-, 22.2%), and IgG2 antibodies (SP-, 56.0%; AP-, 41.7%).CONCLUSIONS The serological status of dogs, as determined by any class or subclass of antibodies, did not accurately distinguish dogs infected with L. (L.) infantum chagasifrom uninfected animals. The inaccuracy of the serological result may impair not only the diagnosis, but also epidemiological investigations and strategies for visceral leishmaniasis control. This complex serological scenario occurring in a visceral leishmaniasis-endemic area highlights the challenges associated with canine diagnosis and points out the difficulties experienced by veterinary clinicians and coordinators of control programs.

Prevalence of Antibodies Associated with Herd Immunity: A New Indicator to Evaluate the Establishment of Herd Immunity and to Decide Immunization Strategies

Objective. To develop a method to estimate the critical prevalence of antibodies associated with herd immunity (pc) and to assess the establishment of herd immunity against measles, mumps, rubella, varicella, and pertussis in Catalonia (Spain) using this method. Methods. The herd immunity is established when the prevalence of antibodies (positive serological results) is higher than pc = Ic Se/PV, where Ic is the prevalence of protected individuals necessary to block the transmission of an infection in the population, Se is the sensitivity of the serological test, and PV is the predictive value of a positive serological result. The establishment of herd immunity was assessed comparing the age-group specific pc with the prevalence of antibodies (p) observed in Catalonia in 2002 in schoolchildren (6—9 years) and individuals aged 14 to 29 years and 45 to 54 years. Results. The herd immunity was not established (p < pc) against measles, mumps, and varicella in schoolchildren aged 6 to 9 years, against measles in individuals aged 15 to 24 years, and against pertussis in all age groups. Based on these results, the measles-mumps-rubella (MMR) vaccine should be given to schoolchildren and individuals aged 15 to 24 years, the varicella vaccine to schoolchildren aged 6 to 9 years, and the diphtheria-tetanus-pertussis (DTaP/dTaP) vaccine to all age groups in order to establish the necessary herd immunity in the population. Conclusion. Serological surveys and the critical prevalence of antibodies can be used to assess the establishment of herd immunity for vaccine-preventable diseases in different population groups, indicating to which of them immunization activities should be prioritized.

COMPARISON OF BIOASSAY AND IMMUNOASSAY OF HUMAN CHORIONIC GONADOTROPHIN IN URINE

ABSTRACT In 39 samples of pregnancy urine, the concentration of human chorionic gonadotrophin (HCG) was estimated biologically by the ovarian hyperaemia reaction in rats, and serologically by the passive haemagglutinationinhibition technique. The results of the bioassays varied from 3 to 150 IU/ml, those of the immunoassays from 5 to 640 IU-eq./ml, and the correlation between the two (calculated for their logarithms) accounted for only 17 per cent of the total variation (r2 = 0.169, P ≈0.01). If the biological activity were estimated from a serological result and the appropriate regression line, the fiducial interval for P = 0.05 would extend from 17 to 610 per cent of the estimate. In a factorial experiment using three anti-HCG sera, three standard and three sensitizing preparations of HCG, the sensitivity of the serological system (expressed as the endpoint concentration in IU of HCG) varied considerably between the 27 combinations of the 3 factors, but there was no interaction between the latter. From these data and those of other authors, it is concluded that immunoassays based on haemagglutination inhibition cannot replace bioassays in the estimation of HCG, as distinct from its hypothetical metabolites or other related antigens, unless specificity has been demonstrated. The well-documented reliability of serological pregnancy tests is, of course, not in dispute. Attention is drawn to the fact that »statistically significant« correlation does not guarantee analytically acceptable agreement between two methods of assay.