The effects of malaria and intermittent preventive treatment during pregnancy on fetal anemia in Malawi

Safety and immunogenicity of varied doses of R21/Matrix-M™ vaccine at three years follow-up: A phase 1b age de-escalation, dose-escalation trial in adults, children, and infants in Kilifi-Kenya

Background

Falciparum malaria remains a global health problem. Two vaccines, based on the circumsporozoite antigen, are available. RTS, S/AS01 was recommended for use in 2021 following the advice of the World Health Organisation (WHO) Strategic Advisory Group of Experts (SAGE) on Immunization and WHO Malaria Policy Advisory Group (MPAG). It has since been pre-qualified in 2022 by the WHO. R21 is similar to RTS, S/AS01, and recently licensed in Nigeria, Ghana and Burkina Faso following Phase 3 trial results.

Methods

We conducted a Phase 1b age de-escalation, dose escalation bridging study after a change in the manufacturing process for R21. We recruited healthy adults and children and used a three dose primary vaccination series with a booster dose at 1-2 years. Variable doses of R21 and adjuvant (Matrix-M ™) were administered at 10µgR21/50 µg Matrix-M™, 5µgR21/25µg Matrix-M™ and 5µgR21/50µg Matrix-M™ to 20 adults, 20 children, and 51 infants.

Results

Self-limiting adverse events were reported relating to the injection site and mild systemic symptoms. Two serious adverse events were reported, neither linked to vaccination. High levels of IgG antibodies to the circumsporozoite antigen were induced, and geometric mean titres in infants, the target group, were 1.1 (0.9 to 1.3) EU/mL at day 0, 10175 (7724 to 13404) EU/mL at day 84 and (following a booster dose at day 421) 6792 (5310 to 8687) EU/mL at day 456.

Conclusion

R21/Matrix-M™ is safe, and immunogenic when given at varied doses with the peak immune response seen in infants 28 days after a three dose primary vaccination series given four weeks apart. Antibody responses were restored 28 days after a 4 th dose given one year post a three dose primary series in the young children and infants.

Registration

Clinicaltrials.gov (NCT03580824; 9 th of July 2018; Pan African Clinical Trials Registry (PACTR202105682956280; 17 th May 2021).

Fetal Cytokine Balance, Erythropoietin and Thalassemia but Not Placental Malaria Contribute to Fetal Anemia Risk in Tanzania

Fetal anemia is common in malaria-endemic areas and a risk factor for anemia as well as mortality during infancy. Placental malaria (PM) and red cell abnormalities have been proposed as possible etiologies, but the relationship between PM and fetal anemia has varied in earlier studies, and the role of red cell abnormalities has not been studied in malaria-endemic areas. In a Tanzanian birth cohort study designed to elucidate the pathogenesis of severe malaria in young infants, we performed a cross-sectional analysis of risk factors for fetal anemia. We determined PM status, newborn red cell abnormalities, and maternal and cord blood levels of iron regulatory proteins, erythropoietin (EPO), cytokines and cytokine receptors. We examined the relationship between these factors and fetal anemia. Fetal anemia was present in 46.2% of the neonates but was not related to PM. Maternal iron deficiency was common (81.6%), most frequent in multigravidae, and interacted with parity to modify risk of fetal anemia, but it was not directly related to risk. Among offspring of iron-deficient women, the odds of fetal anemia increased with fetal α⁺-thalassemia, as well as these patterns of cord blood cytokines: increased cord IL-6, decreased TNF-RI, and decreased sTfR. The EPO response to fetal anemia was low or absent and EPO levels were significantly decreased in newborns with the most severe anemia. This study from an area of high malaria transmission provides evidence that 1) fetal α⁺-thalassemia and cytokine balance, but not PM at delivery, are related to fetal anemia; 2) maternal iron deficiency increases the risk that other factors may cause fetal anemia; and 3) fetal anemia has a multifactorial etiology that may require a variety of interventions, although measures that reduce maternal iron deficiency may be generally beneficial.

Prevalence and Associated Risk Factors of Malaria in the First Trimester of Pregnancy: A Preconceptional Cohort Study in Benin

Background

There is a lack of data on the burden of malaria in the first trimester of pregnancy in Africa, mainly because pregnant women generally attend the maternity clinic late. Bed nets are rarely provided to women before the second trimester of pregnancy and intermittent preventive treatment with sulfadoxine-pyrimethamine is not recommended before the second trimester, leaving women insufficiently or not protected in early pregnancy.

Methods

To assess the burden of first trimester malaria, 387 women were followed up monthly from preconception to delivery. They were screened for malaria monthly from early pregnancy until delivery. A logistic multilevel model was used to assess maternal factors associated with malaria during the first trimester.

Results

The proportion of women with at least 1 microscopic malaria infection during the first trimester of pregnancy was 20.8%. Women infected with malaria preconception were more likely to be infected during the first trimester (adjusted odds ratio: 2.68; 95% confidence interval, 1.24-5.78). Early gestational age was also positively correlated with malaria infection.

Conclusions

Using a preconceptional study design, we showed that malaria was highly prevalent in early pregnancy. This calls for the assessment of new strategies that could protect women as soon as the first trimester.

The protective effectiveness of control interventions for malaria prevention: a systematic review of the literature

Background: Thanks to a considerable increase in funding, malaria control interventions (MCI) whose efficacy had been demonstrated by controlled trials have been largely scaled up during the last decade. Nevertheless, it was not systematically investigated whether this efficacy had been preserved once deployed on the field. Therefore, we sought the literature to assess the disparities between efficacy and effectiveness and the effort to measure the protective effectiveness (PE) of MCI.

Methods: The PubMed database was searched for references with keywords related to malaria, to control interventions for prevention and to study designs that allow for the measure of the PE against parasitemia or against clinical outcomes.

Results: Our search retrieved 1423 references, and 162 articles were included in the review. Publications were scarce before the year 2000 but dramatically increased afterwards. Bed nets was the MCI most studied (82.1%). The study design most used was a cross-sectional study (65.4%). Two thirds (67.3%) were conducted at the district level or below, and the majority (56.8%) included only children even if the MCI didn’t target only children. Not all studies demonstrated a significant PE from exposure to MCI: 60.6% of studies evaluating bed nets, 50.0% of those evaluating indoor residual spraying, and 4/8 showed an added PE of using both interventions as compared with one only; this proportion was 62.5% for intermittent preventive treatment of pregnant women, and 20.0% for domestic use of insecticides.

Conclusions: This review identified numerous local findings of low, non-significant PE –or even the absence of a protective effect provided by these MCIs. The identification of such failures in the effectiveness of MCIs advocates for the investigation of the causes of the problem found. Ideal evaluations of the PE of MCIs should incorporate both a large representativeness and an evaluation of the PE stratified by subpopulations.

The effects of co-infection with human parvovirus B19 and Plasmodium falciparum on type and degree of anaemia in Ghanaian children

OBJECTIVE

To determin the extent to which parvovirus B19 (B19V) and co-infection of B19V and malaria contribute to risk of anaemia in children.

METHODS

B19V DNA and malaria parasites were screened for 234 children at the PML Children's Hospital in Accra. The role of B19V and co-infection with B19V and malaria in anaemia was evaluated by analysing full blood cell counts, malaria and B19V DNA results from these children.

RESULTS

The prevalence of B19V, malaria and co-infection with B19V and malaria was 4.7%, 41.9% and 2.6%, respectively. Malaria posed a greater risk in the development of mild anaemia compared to severe anaemia (OR=5.28 vrs 3.15) whereas B19V posed a higher risk in the development of severe anaemia compared to mild anaemia (OR=4.07 vrs 1.00) from a non-anaemic child. Persons with co-infection with B19V and malaria had 2.23 times the risk (95% CI=0.40-12.54) of developing severe anaemia should they already have a mild anaemia. The degree of anaemia was about three times affected by co-infection (Pillai's trace=0.551, P=0.001) as was affected by malaria alone (Pillai's trace=0.185, P=0.001). B19V alone did not significantly affect the development of anaemia in a non-anaemic child. Microcytic anaemia was associated with B19V and co-infection with B19V and malaria more than normocytic normochromic anaemia.

CONCLUSIONS

B19V was associated with malaria in cases of severe anaemia. The association posed a significant risk for exacerbation of anaemia in mild anaemic children. B19V and co-infection with B19V and malaria may be associated with microcytic anaemia rather than normocytic normochromic anaemia as seen in cases of B19V infection among persons with red cell abnormalities.

The association of parasitic infections in pregnancy and maternal and fetal anemia: a cohort study in coastal Kenya

Background

Relative contribution of these infections on anemia in pregnancy is not certain. While measures to protect pregnant women against malaria have been scaling up, interventions against helminthes have received much less attention. In this study, we determine the relative impact of helminthes and malaria on maternal anemia.

Methods

A prospective observational study was conducted in coastal Kenya among a cohort of pregnant women who were recruited at their first antenatal care (ANC) visit and tested for malaria, hookworm, and other parasitic infections and anemia at enrollment. All women enrolled in the study received presumptive treatment with sulfadoxine-pyrimethamine, iron and multi-vitamins and women diagnosed with helminthic infections were treated with albendazole. Women delivering a live, term birth, were also tested for maternal anemia, fetal anemia and presence of infection at delivery.

Principal Findings

Of the 706 women studied, at the first ANC visit, 27% had moderate/severe anemia and 71% of women were anemic overall. The infections with highest prevalence were hookworm (24%), urogenital schistosomiasis (17%), trichuria (10%), and malaria (9%). In adjusted and unadjusted analyses, moderate/severe anemia at first ANC visit was associated with the higher intensities of hookworm and P. falciparum microscopy-malaria infections. At delivery, 34% of women had moderate/severe anemia and 18% of infants' cord hemoglobin was consistent with fetal anemia. While none of the maternal infections were significantly associated with fetal anemia, moderate/severe maternal anemia was associated with fetal anemia.

Conclusions

More than one quarter of women receiving standard ANC with IPTp for malaria had moderate/severe anemia in pregnancy and high rates of parasitic infection. Thus, addressing the role of co-infections, such as hookworm, as well as under-nutrition, and their contribution to anemia is needed.

International guidelines recommend routine prevention and treatments which are safe and effective during pregnancy to reduce hookworm, malaria and other infections among pregnant women living in geographic areas where these infections are prevalent. Despite their effectiveness, programs to address common infections such as hookworm, schistosomiasis and malaria during pregnancy have not been widely adopted. Hookworm, malaria and other infections have been associated with anemia in children, but the studies on the impact of these infections on anemia in pregnancy have not been as clear. This study was undertaken to evaluate the prevalence of parasitic infections among women attending antenatal care which provided the nationally recommended malaria preventive treatment program in coastal Kenya. At the first ANC visit, more than 70% of women were anemic, nearly one-fourth had hookworm and about 10% had malaria. Women with high levels of hookworm or malaria infections were at risk of anemia.

Utilization of intermittent preventive treatment for malaria among pregnant women attending antenatal clinics in health facilities of Cross River State, Nigeria

Objective

This study assessed the utilization of intermittent preventive treatment with sulfadoxine–pyrimethamine for the prevention of malaria in pregnancy against the national treatment policy among women attending health care facilities in Cross River State, Nigeria.

Methods

A clinical audit was carried out between January 2012 and March 2012 using case records of pregnant women who received antenatal care in health facilities in the state. Facilities were selected by simple random sampling. Information on the frequency of antenatal clinic (ANC) visits by the women, as well as parity, age, and adherence to intermittent preventive treatment (IPTp) doses was obtained using an audit checklist.

Results

A total of 322 pregnant women were assessed across 36 health care facilities. In addition, 246 (76%) of them attended the ANC in public health facilities. Age, parity, and gestational age at booking were recorded in more than 95% of the cases evaluated. The audit showed that 13.7% of the women did not utilize IPTp, 53.1% had one dose of IPTp (IPTp1), 24.2% had two doses of IPTp (IPTp2), while 3.1% had three doses of IPTp (IPTp3). The overall utilization of two doses or more of IPTp (IPTp2+) was 30.7%.

Conclusion

There was good documentation of the basic obstetric information of pregnant women in the health care facilities examined in this study, but the overall utilization of IPTp was very low. Efforts at ensuring early ANC booking and regular visits may be a potential means of increasing IPTp utilization in health care facilities in the state.