Pregnancy and contraceptive use among women participating in an HIV prevention trial in Tanzania.

OBJECTIVES: Information on pregnancy rates and factors associated with pregnancy and contraceptive use is important for clinical trials in women in sub-Saharan Africa where withdrawal of investigational products may be required in the event of pregnancy with a consequent effect on sample size and trial power. METHODS: A prospective cohort analysis of pregnancy and contraceptive use was conducted in Tanzanian women enrolled in a randomised placebo-controlled trial of herpes simplex virus-suppressive therapy with acyclovir to measure the effect on HIV incidence in HIV-negative women and on genital and plasma HIV viral load in HIV-positive women. The cohort was followed every 3 months for 12-30 months. Women at each visit were categorised into users or non-users of contraception. Pregnancy rates and factors associated with pregnancy incidence and contraceptive use were measured. RESULTS: Overall 254 of 1305 enrolled women became pregnant at least once during follow-up (pregnancy rate: 12.0/100 person-years). Younger age, being unmarried, higher baseline parity and changes in contraceptive method during follow-up were independently associated with pregnancy. Having paid sex and being HIV positive were associated with lower risk of pregnancy. Uptake of contraception was associated with young age, being unmarried, occupation, parity and the number and type of sexual partners. CONCLUSIONS: Data on use of contraceptive methods and risk factors for pregnancy can help to guide decisions on trial eligibility and the need for additional counselling. Mandatory reliable contraceptive use in study participants may be required to reduce pregnancy rates in studies where pregnancy is contraindicated

Kinetics of antibodies against pneumococcal proteins and their relationship to nasopharyngeal carriage in the first two months of life.

INTRODUCTION: The currently used Streptococcus pneumoniae vaccines have had a significant impact on the pneumococcal diseases caused by the serotypes they cover. Their limitations have stimulated a search for alternate vaccines that will cover all serotypes, be affordable and effective in young children. Pneumococcal protein antigens are potential vaccine candidates that may meet some of the shortfalls of the current vaccines. Thus, this study aimed to determine the relationship between antibodies against pneumococcal protein antigens and nasopharyngeal carriage in infants. METHODS: One hundred and twenty mother-infant pairs were enrolled into the study. They had nasopharyngeal swabs(NPS) taken at birth and every two weeks for the first eight weeks after delivery, and blood samples were obtained at birth and every four weeks for the first eight weeks after delivery. Nasopharyngeal carriage of S. pneumoniae was determined from the NPS and antibodies against the pneumococcal proteins CbpA, PspA and rPly were measured in the blood samples. RESULTS: The S. pneumoniae carriage rate in infants increased to that of mothers by eight weeks of age. The odds of carriage in infants was 6.2 times (95% CI: 2.0-18.9) higher when their mothers were also carriers. Bacterial density in infants was lower at birth compared to their mothers (p = 0.004), but increased with age and became higher than that of their mothers at weeks 4 (p = 0.009), 6 (p = 0.002) and 8 (p<0.0001). At birth, the infants' antibodies against CbpA, and rPly pneumococcal protein antigens were similar, but that of PspA was lower (p<0.0001), compared to their mothers. Higher antibody concentrations to CbpA [OR (95% CI): 0.49 (0.26-0.92, p = 0.03)], but not PspA and rPly, were associated with protection against carriage in the infants. CONCLUSION: Naturally induced antibodies against the three pneumococcal protein antigens were transferred from mother to child. The proportion of infants with nasopharyngeal carriage and the bacterial density of S. pneumoniae increased with age within the first eight weeks of life. Higher concentrations of antibodies against CbpA, but not PspA and rPly, were associated with reduced risk of nasopharyngeal carriage of S. pneumoniae in infants

Staphylococcus aureus Bacteremia in Children of Rural Areas of The Gambia, 2008–2015

Staphylococcus aureus bacteremia is a substantial cause of childhood disease and death, but few studies have described its epidemiology in developing countries. Using a population-based surveillance system for pneumonia, sepsis, and meningitis, we estimated S. aureus bacteremia incidence and the case-fatality ratio in children <5 years of age in 2 regions in the eastern part of The Gambia during 2008–2015. Among 33,060 children with suspected pneumonia, sepsis, or meningitis, we performed blood culture for 27,851; of 1,130 patients with bacteremia, 198 (17.5%) were positive for S. aureus. S. aureus bacteremia incidence was 78 (95% CI 67–91) cases/100,000 person-years in children <5 years of age and 2,080 (95% CI 1,621–2,627) cases/100,000 person-years in neonates. Incidence did not change after introduction of the pneumococcal conjugate vaccine. The case-fatality ratio was 14.1% (95% CI 9.6%–19.8%). Interventions are needed to reduce the S. aureus bacteremia burden in The Gambia, particularly among neonates

Pneumococcal Antibody Concentrations and Carriage of Pneumococci more than 3 Years after Infant Immunization with a Pneumococcal Conjugate Vaccine

BACKGROUND: A 9-valent pneumococcal conjugate vaccine (PCV-9), given in a 3-dose schedule, protected Gambian children against pneumococcal disease and reduced nasopharyngeal carriage of pneumococci of vaccine serotypes. We have studied the effect of a booster or delayed primary dose of 7-valent conjugate vaccine (PCV-7) on antibody and nasopharyngeal carriage of pneumococci 3-4 years after primary vaccination. METHODOLOGY/PRINCIPAL FINDINGS: We recruited a subsample of children who had received 3 doses of either PCV-9 or placebo (controls) into this follow-up study. Pre- and post- PCV-7 pneumococcal antibody concentrations to the 9 serotypes in PCV-9 and nasopharyngeal carriage of pneumococci were determined before and at intervals up to 18 months post-PCV-7. We enrolled 282 children at a median age of 45 months (range, 38-52 months); 138 had received 3 doses of PCV-9 in infancy and 144 were controls. Before receiving PCV-7, a high proportion of children had antibody concentrations >0.35 µg/mL to most of the serotypes in PCV-9 (average of 75% in the PCV-9 and 66% in the control group respectively). The geometric mean antibody concentrations in the vaccinated group were significantly higher compared to controls for serotypes 6B, 14, and 23F. Antibody concentrations were significantly increased to serotypes in the PCV-7 vaccine both 6-8 weeks and 16-18 months after PCV-7. Antibodies to serotypes 6B, 9V and 23F were higher in the PCV-9 group than in the control group 6-8 weeks after PCV-7, but only the 6B difference was sustained at 16-18 months. There was no significant difference in nasopharyngeal carriage between the two groups. CONCLUSIONS/SIGNIFICANCE: Pneumococcal antibody concentrations in Gambian children were high 34-48 months after a 3-dose primary infant vaccination series of PCV-9 for serotypes other than serotypes 1 and 18C, and were significantly higher than in control children for 3 of the 9 serotypes. Antibody concentrations increased after PCV-7 and remained raised for at least 18 months

Impact of the introduction of pneumococcal conjugate vaccination on invasive pneumococcal disease and pneumonia in The Gambia: 10 years of population-based surveillance.

BACKGROUND: The Gambia introduced seven-valent pneumococcal conjugate vaccine (PCV7) in August 2009, followed by PCV13 in May, 2011, using a schedule of three primary doses without a booster dose or catch-up immunisation. We aimed to assess the long-term impact of PCV on disease incidence. METHODS: We did 10 years of population-based surveillance for invasive pneumococcal disease (IPD) and WHO defined radiological pneumonia with consolidation in rural Gambia. The surveillance population included all Basse Health and Demographic Surveillance System residents aged 2 months or older. Nurses screened all outpatients and inpatients at all health facilities using standardised criteria for referral. Clinicians then applied criteria for patient investigation. We defined IPD as a compatible illness with isolation of Streptococcus pneumoniae from a normally sterile site (cerebrospinal fluid, blood, or pleural fluid). We compared disease incidence between baseline (May 12, 2008-May 11, 2010) and post-vaccine years (2016-2017), in children aged 2 months to 14 years, adjusting for changes in case ascertainment over time. FINDINGS: We identified 22 728 patients for investigation and detected 342 cases of IPD and 2623 cases of radiological pneumonia. Among children aged 2-59 months, IPD incidence declined from 184 cases per 100 000 person-years to 38 cases per 100 000 person-years, an 80% reduction (95% CI 69-87). Non-pneumococcal bacteraemia incidence did not change significantly over time (incidence rate ratio 0·88; 95% CI, 0·64-1·21). We detected zero cases of vaccine-type IPD in the 2-11 month age group in 2016-17. Incidence of radiological pneumonia decreased by 33% (95% CI 24-40), from 10·5 to 7·0 per 1000 person-years in the 2-59 month age group, while pneumonia hospitalisations declined by 27% (95% CI 22-31). In the 5-14 year age group, IPD incidence declined by 69% (95% CI -28 to 91) and radiological pneumonia by 27% (95% CI -5 to 49). INTERPRETATION: Routine introduction of PCV13 substantially reduced the incidence of childhood IPD and pneumonia in rural Gambia, including elimination of vaccine-type IPD in infants. Other low-income countries can expect substantial impact from the introduction of PCV13 using a schedule of three primary doses. FUNDING: Gavi, The Vaccine Alliance; Bill & Melinda Gates Foundation; UK Medical Research Council; Pfizer Ltd

Kinetics of antibodies against pneumococcal proteins and their relationship to nasopharyngeal carriage in the first two months of life

<div><p>Introduction</p><p>The currently used <i>Streptococcus pneumoniae</i> vaccines have had a significant impact on the pneumococcal diseases caused by the serotypes they cover. Their limitations have stimulated a search for alternate vaccines that will cover all serotypes, be affordable and effective in young children. Pneumococcal protein antigens are potential vaccine candidates that may meet some of the shortfalls of the current vaccines. Thus, this study aimed to determine the relationship between antibodies against pneumococcal protein antigens and nasopharyngeal carriage in infants.</p><p>Methods</p><p>One hundred and twenty mother-infant pairs were enrolled into the study. They had nasopharyngeal swabs(NPS) taken at birth and every two weeks for the first eight weeks after delivery, and blood samples were obtained at birth and every four weeks for the first eight weeks after delivery. Nasopharyngeal carriage of <i>S</i>. <i>pneumoniae</i> was determined from the NPS and antibodies against the pneumococcal proteins CbpA, PspA and rPly were measured in the blood samples.</p><p>Results</p><p>The <i>S</i>. <i>pneumoniae</i> carriage rate in infants increased to that of mothers by eight weeks of age. The odds of carriage in infants was 6.2 times (95% CI: 2.0–18.9) higher when their mothers were also carriers. Bacterial density in infants was lower at birth compared to their mothers (p = 0.004), but increased with age and became higher than that of their mothers at weeks 4 (p = 0.009), 6 (p = 0.002) and 8 (p<0.0001). At birth, the infants’ antibodies against <i>CbpA</i>, and <i>rPly</i> pneumococcal protein antigens were similar, but that of <i>PspA</i> was lower (p<0.0001), compared to their mothers. Higher antibody concentrations to <i>CbpA</i> [OR (95% CI): 0.49 (0.26–0.92, p = 0.03)], but not <i>PspA</i> and <i>rPly</i>, were associated with protection against carriage in the infants.</p><p>Conclusion</p><p>Naturally induced antibodies against the three pneumococcal protein antigens were transferred from mother to child. The proportion of infants with nasopharyngeal carriage and the bacterial density of <i>S</i>. <i>pneumoniae</i> increased with age within the first eight weeks of life. Higher concentrations of antibodies against <i>CbpA</i>, but not <i>PspA</i> and <i>rPly</i>, were associated with reduced risk of nasopharyngeal carriage of <i>S</i>. <i>pneumoniae</i> in infants.</p></div

Effects of mother’s log-antibody concentrations against <i>CbpA</i>, <i>PspA</i> and <i>rPly</i> at delivery on infant’s log-antibody concentrations and difference in infant’s antibody concentrations between carriers and non-carriers at birth, 4 and 8 weeks.

<p>Effects of mother’s log-antibody concentrations against <i>CbpA</i>, <i>PspA</i> and <i>rPly</i> at delivery on infant’s log-antibody concentrations and difference in infant’s antibody concentrations between carriers and non-carriers at birth, 4 and 8 weeks.</p

Effects of mother’s log-antibody concentrations against <i>CbpA</i>, <i>PspA</i> and <i>rPly</i> at delivery on infant’s log-antibody concentrations and difference in infant’s antibody concentrations between carriers and non-carriers at birth, 4 and 8 weeks.

<p>Effects of mother’s log-antibody concentrations against <i>CbpA</i>, <i>PspA</i> and <i>rPly</i> at delivery on infant’s log-antibody concentrations and difference in infant’s antibody concentrations between carriers and non-carriers at birth, 4 and 8 weeks.</p

Concentration of antibodies against <i>CbpA</i>, <i>PspA</i> and <i>rPly</i> in mothers’ (closed circles) and cord blood (open circles) at birth.

<p>The horizontal black lines represent the average log-plasma antibody concentrations. The p values indicate the difference between the average antibody concentration for the specific pneumococcal antigen between mothers’ venous blood and infants’ cord blood at birth.</p