Malaria infections during pregnancy are known to cause poor maternal and fetal outcomes and in Africa are thought to cause as many as 50,000 maternal deaths and 200,000 stillbirths each year. Tools such as bed nets and intermittent therapy have been inadequate, but immunizing women before pregnancy looks promising as a new strategy, researchers reported yesterday in The Lancet Infectious Diseases.

Researchers from the National Institutes of Health and their partners in Mali tested the strategy using PfSPZ, an investigational attenuated vaccine based on Plasmodium falciparum sporozoites made by Sanaria, based in Rockville, Maryland. Earlier clinical trials in Africa had found that the vaccine was safe and effective. 

In Mali, researchers enrolled 300 women who planned on getting pregnant in the coming year. Participants were categorized into three groups. Two received either a low or high dose of the vaccine, and the third got a normal-saline placebo vaccine. 

Participants received three doses, each a month apart. Investigators monitored the women for two malaria seasons over nearly 2 years. The team also tracked women who were pregnant over that period and followed-up on the health of the newborns through the first birthday.

Durable protection across 2 years

The vaccine was safe for both women and their babies. In the first year of the trial, 55 women became pregnant within 6 weeks of the third vaccine dose. Vaccine efficacy was 65% in those who received the lower dose and 86% in participants who got the higher dose. Of 155 women who became pregnant in both study years, efficacy was 57% for the lower dose and 49% for the higher dose.

In the next steps, the group will examine the safety of the PfSPZ vaccine during pregnancy and do a larger study on its preconception use.

In a related editorial in the same issue, Stephanie Yanow, PhD, and Daniel Ferrer Vinals, PhD, a cell biologist and chemical biologist, respectively, at the University of Alberta, wrote that the vaccine showed durable protection over 2 years without boosting, unlike other malaria vaccines. They said the preconception trial builds a good framework for assessing the vaccine in pregnant women, who are often excluded from trials.

Compared to last year at this time, global cholera cases have declined 31%, but deaths are 34% higher, the World Health Organization (WHO) said today in its latest update, which includes data received in July.

For July, 17 countries reported nearly 52,000 cases, along with 223 deaths. Four WHO regions reported cases, with the Eastern Mediterranean region hit hardest, followed by the African region. 

Since late July, Nepal has reported new cholera clusters from several districts. 

Cholera vaccine shortage persists

The WHO said the response to the outbreaks is still hampered by a shortage of oral cholera vaccine, with 105 million doses requested by 18 countries since January 2023, nearly double the 55 million doses produced over that period.

The WHO said the global risk is still very high and is considered a grade 3 emergency. It added that transmission dynamics are increasingly complex, reflecting factors that cross county borders, such as population mobility, natural disasters, and climate change.

Antibiotics given to pregnant women prior to cesarean section have limited effects on infant gut microbiome composition, researchers reported yesterday in Cell Host & Microbe.

In a randomized trial conducted in the Netherlands, investigators found that antibiotics given prior to incision to prevent maternal infections and neonatal sepsis subtly affected bacterial strain variability and antibiotic resistance gene abundance in infants. But feeding mode had a much bigger impact on infant microbial composition.

Administering antibiotics 20 minutes before incision is widely recommend and has been found to reduce maternal risk of infection, but few studies have looked at the impact on the infant gut microbiome.

"We decided to conduct this study because it addresses a significant clinical question with possibly profound implications for infant health," first and corresponding author Trishla Sinha, MD, of University Medical Center Groningen, said in a press release from Cell Press. "Mothers often ask whether the antibiotics they take influence their child, and this study can provide assurance that they have only small effects on infant gut microbiome."

Feeding mode had larger impact on gut microbiome composition

For the trial, investigators enrolled 28 mother-infant pairs, assigning 12 of the mothers to receive antibiotics before skin incision and 16 to receive them after the umbilical cord was clamped—a practice that was common prior to 2015 in part to avoid exposing newborns to antibiotics. The World Health Organization recommended in 2015 that antibiotics be administered before the incision.

Analysis of 172 infant fecal microbiome samples collected at eight time points after birth, along with data from 79 infants in two similar trials, found no statistically significant differences in the two groups in terms of bacterial diversity and species richness. Differences at the bacterial strain level and in the load of antibiotic resistance genes in infants born to mothers who had received antibiotics prior to incision were very small.

Mothers often ask whether the antibiotics they take influence their child, and this study can provide assurance that they have only small effects on infant gut microbiome.

Feeding mode explained 12% of the variation in infant gut microbiome composition and also had a profound effect on the babies' bile acid composition.

The investigators say the findings need to be validated in larger-scale and long-term studies, and further research is needed on the long-term health implications for pregnant women and infants.