Guidelines and considerations for testing malaria vaccines in pregnant women

Menéndez, Clara; Alonso, Pedro L.

doi:10.4161/hv.6.1.10331

Cited by 4 publications

(3 citation statements)

References 45 publications

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“…However, there are still several uncertainties, including the number of antigenic variants to be combined for an optimal response, the timing of the vaccine, e.g. during pregnancy or at puberty, whether only first pregnancies should be targeted, and the length of follow up for children born to vaccinated mothers 111–112,117…”

Section: Prevention and Treatmentmentioning

confidence: 99%

Malaria in Pregnancy

Takem¹,

D’Alessandro

2013

Mediterr J Hematol Infect Dis

133

102

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Pregnant women have a higher risk of malaria compared to non-pregnant women. This review provides an update on knowledge acquired since 2000 on P. falciparum and P.vivax infections in pregnancy. Maternal risk factors for malaria in pregnancy (MiP) include low maternal age, low parity, and low gestational age. The main effects of MIP include maternal anaemia, low birth weight (LBW), preterm delivery and increased infant and maternal mortality.P. falciparum infected erythrocytes sequester in the placenta by expressing surface antigens, mainly variant surface antigen (VAR2CSA), that bind to specific receptors, mainly chondroitin sulphate A. In stable transmission settings, the higher malaria risk in primigravidae can be explained by the non-recognition of these surface antigens by the immune system. Recently, placental sequestration has been described also for P.vivax infections. The mechanism of preterm delivery and intrauterine growth retardation is not completely understood, but fever (preterm delivery), anaemia, and high cytokines levels have been implicated.Clinical suspicion of MiP should be confirmed by parasitological diagnosis. The sensitivity of microscopy, with placenta histology as the gold standard, is 60% and 45% for peripheral and placental falciparum infections in African women, respectively. Compared to microscopy, RDTs have a lower sensitivity though when the quality of microscopy is low RDTs may be more reliable. Insecticide treated nets (ITN) and intermittent preventive treatment in pregnancy (IPTp) are recommended for the prevention of MiP in stable transmission settings. ITNs have been shown to reduce malaria infection and adverse pregnancy outcomes by 28–47%. Although resistance is a concern, SP has been shown to be equivalent to MQ and AQ for IPTp. For the treatment of uncomplicated malaria during the first trimester, quinine plus clindamycin for 7 days is the first line treatment and artesunate plus clindamycin for 7 days is indicated if this treatment fails; in the 2nd and 3rd trimester first line treatment is an artemisinin-based combination therapy (ACT) known to be effective in the region or artesunate and clindamycin for 7 days or quinine and clindamycin. For severe malaria, in the second and third trimester parenteral artesunate is preferred over quinine. In the first trimester, both artesunate and quinine (parenteral) may be considered as options. Nevertheless, treatment should not be delayed and should be started immediately with the most readily available drug.

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Section: Prevention and Treatmentmentioning

confidence: 99%

Malaria in Pregnancy

Takem¹,

D’Alessandro

2013

Mediterr J Hematol Infect Dis

133

102

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“…Using these vaccines alone may not produce a sufficient immune response to confer long-lasting protection against PAM [124]. Therefore, a 'primer' of naked antigen DNA could be provided to stimulate the initial immune response.…”

Section: Methods Of Delivering a Pam Vaccinementioning

confidence: 99%

Understanding How Plasmodium falciparum Binds to the Placenta and Produces Pathology Provides a Rationale for Pregnancy-Associated Malaria Vaccine Development

Morley¹

2012

TOVACJ

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By adulthood repeated exposure to Plasmodium falciparum, the causative agent of the most severe form of malaria in humans, can induce semi-immunity to clinical infection. During pregnancy, however, there is a striking recurrence of severe disease, a syndrome described as pregnancy-associated malaria (PAM). This is caused by P. falciparum-infected erythrocytes binding to receptors on the placental endothelium that are expressed uniquely during pregnancy. This subset of parasites binds by virtue of expressing a cell surface antigen that is the ligand for the corresponding endothelial receptor, thereby providing a selective pressure for its clonal expansion. The antigen also triggers a protective antibody-mediated immune response. With subsequent pregnancies and further exposure to these variant parasites, antibodies develop earlier and women may experience milder infections. Women with PAM exhibit more severe malaria infections than do non-gravid women, with 2,500-10,000 deaths each year due to haemolytic anaemia. PAM also has a detrimental effect on the foetus, increasing the risk of low birth weight, which causes 60,000-200,000 infant deaths annually in sub-Saharan Africa. Current research aims to produce a vaccine to stimulate development of antibodies which would be protective against infection with wild-type parasites. This is hampered by significant diversity in variant surface antigens and available vaccine candidates may only protect women living in malaria-endemic areas. While placental-parasite interactions are not sufficiently understood, incremental progress is being made towards producing an effective vaccine. This review focuses on the molecular structures involved in binding to consider the prospects for a vaccine mimicking naturally-acquired immunity to PAM.

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“…IPTp has been proven to have a great impact on placental malaria (PM), LBW, peripheral malaria infection at delivery, and infant mortality so increasing the number of IPTp-SP doses given is a priority. In Burkina Faso, the National Malaria Control Program (NMCP) has recommended at least 3 doses of IPTp-SP but available information suggests that only 31.5% of eligible women met this recommendation despite observed high levels of antenatal clinic (ANC) attendance [ 1 , 16 , 17 ]. Strategies to increase the number of IPTp-SP doses and the coverage using reminders could improve this health intervention's effectiveness.…”

Section: Introductionmentioning

confidence: 99%

Impact and operational feasibility of adding malaria infection screening using an ultrasensitive RDT for placental and fetal outcomes in an area of high IPTP-SP coverage in Burkina Faso: the ASSER MALARIA pilot study protocol

Tahita¹,

Sondo²,

Kaboré³

et al. 2022

Pilot Feasibility Stud

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Background Malaria infection during pregnancy (MIP) is not only deleterious to the woman, but it also puts her fetus at increased risk of adverse outcomes, such as preterm delivery, low birth weight, and intrauterine growth retardation. Additionally, all-cause mortality during the first year of life in babies born to women with malaria during pregnancy is also increased. Many interventions such as IPTp-SP and long-lasting insecticidal nets have proven to be efficient at reducing malaria in pregnancy burden but adherence to recommended policies remains poor. In sub-Saharan Africa, malaria in pregnancy is often asymptomatic and many malaria infections may be missed due to the inadequate performance of the current rapid diagnostic test to detect low-level parasitemias. Therefore, additional strategies such as intermittent screening with ultrasensitive rapid diagnostic tests and treatment with an effective artemisinin-based combination therapy in addition to IPTp-SP could reduce placental malaria, peripheral malaria infection at delivery, and low birth weight. Methods This pilot 2-group randomized open trial with a nested qualitative social behavioral will be carried out in Nanoro district in which 340 pregnant women will be recruited. Pregnant women will be randomized into two groups and followed on a monthly basis until delivery. In the intervention group, monthly screening using ultrasensitive rapid diagnostic tests and treatment of those found to be infected with dihydroartemisinin-piperaquine will be performed. In addition, a reminder will be sent to increase the uptake of IPTp-SP doses per woman. During scheduled and unscheduled visits, malaria infection, hemoglobin level, and other clinical outcomes will be assessed and compared by the group. The primary feasibility outcome will evaluate the study site's capacity to enroll participants and the women’s perception and acceptability of the intervention. The primary clinical outcome will be the prevalence of placental malaria at delivery. Discussion The present protocol aims to evaluate the feasibility on a large-scale and also to demonstrate the impact and the operational feasibility of additional screening with ultrasensitive rapid diagnostic tests and treatment with DHA-PQ on placental malaria, low birth weight, and peripheral malaria infection at delivery in a high-burden setting in Burkina Faso. Trial registration ClinicalTrials.gov, ID: NCT04147546 (14 October 2019).

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Guidelines and considerations for testing malaria vaccines in pregnant women

Cited by 4 publications

References 45 publications

Malaria in Pregnancy

Malaria in Pregnancy

Understanding How Plasmodium falciparum Binds to the Placenta and Produces Pathology Provides a Rationale for Pregnancy-Associated Malaria Vaccine Development

Impact and operational feasibility of adding malaria infection screening using an ultrasensitive RDT for placental and fetal outcomes in an area of high IPTP-SP coverage in Burkina Faso: the ASSER MALARIA pilot study protocol

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