Pregnancy & Mosquitoes: Do we need a malaria vaccine for pregnant women?

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By Ada Ezeokoli (MHTF Research Assistant)

Vaccine injection in the arm
Do pregnant women need a malaria vaccine? Photo by Karolina Grabowska from Pexels

Atinuke, a young professional in Abuja, Nigeria, was watching CNN when she saw the news that the World Health Organization (WHO) had recommended use of the malaria vaccine for children in endemic areas. Atinuke was in the third trimester of her first pregnancy, and she received the news with mixed emotions.

“I haven’t had an antenatal class since they announced the vaccine, but I saw on the news that it is only between 30-40% effective against malaria and lasts for four years. So, it’s groundbreaking news but I don’t want to get excited because I don’t think we are there yet, especially here in Nigeria where we have one the highest burdens of malaria,” she said.

WHO recommends the vaccine for children at risk in sub-Saharan Africa and in other regions with moderate to high malaria transmission. The recommendation was based on results from an ongoing pilot program in Ghana, Kenya and Malawi that has reached more than 800,000 children since 2019.

WHO Director General Dr. Tedros Adhanom Ghebreyesus called the recommendation a historic moment and a breakthrough for science, child health, and malaria control. “Using this vaccine on top of existing tools to prevent malaria could save tens of thousands of young lives each year,” he said.

The announcement is a step forward for the global health system in the fight against malaria, a disease from which more than 260,000 African children under the age of five die every year. Key findings from the vaccine pilots show that the vaccine is feasible to deliver, improves health, increases equity in access to malaria prevention, is safe, has not reduced the uptake of bed nets or other childhood vaccinations, and has reduced the incidences of deadly severe malaria by 30%. The vaccine is also cost-effective in areas of moderate to high malaria transmission.

Do pregnant women in malaria-endemic regions need a malaria vaccine?

Pregnant women are also highly susceptible to malaria and being infected while pregnant can lead to deaths of mothers and infants if no treatment is provided to prevent and treat the disease.

A 2020 study published in The Lancet estimates that 10 to 20 percent of maternal mortality in countries where malaria is endemic is malaria-related. The study notes that malaria is associated with a 3–4 times increased risk of miscarriage and a substantially increased risk of stillbirth.

Atinuke noted that during her antenatal classes, “They tell you to be careful about malaria, to use your bed net and insecticide, especially as we enter the rainy season. They just tell you to be careful to avoid mosquito bites as much as possible.”

She was also given medication to prevent malaria. “In my second trimester I was given anti-malarial drugs as a form of prophylaxis to prevent malaria,” she said.

Infographic on Malaria In Pregnancy

WHO recommends three or more doses of IPTp-SP intermittent preventive treatment of malaria in pregnancy using sulfadoxine-pyrimethamine (IPTp-SP) for all pregnant women living in areas of moderate-to-high malaria transmission in Africa; the preventive treatment should start as early as possible in the 2nd trimester. IPTp has been shown to reduce anemia and low birth weight, a major cause of infant mortality.

The researchers in the Lancet study note that this is not enough to protect women throughout their pregnancy, pointing out that this current process suffers frominadequate dosing, poor (few and late) antenatal clinic attendance, increasing antimalarial drug resistance, and decreasing naturally acquired maternal immunity due to the decreased incidence of malaria.”

They conclude that the prevention of all malaria infections by providing sustained exposure to effective concentrations of antimalarial drugs is key to reducing the adverse effects of malaria in pregnancy.

Atinuke says she has not gotten sick or tested positive for malaria since she got pregnant, and believes the antimalarial drugs have been helpful, in addition to the safety precautions that she has taken.

Big questions around development, utilization, and cost of vaccines

While malaria vaccine development has made significant progress in recent years, no trials of malaria vaccines have been conducted in pregnant women, according to this study. Discussions around the rationale and design of malaria vaccine trials in pregnant women “highlighted the progress made in the field of maternal immunization for other infectious diseases, and the evolving regulatory and ethical environment, all of which support a new emphasis on testing malaria vaccines that offer direct benefits to pregnant women.”

There are no current indications that expanding the vaccine to pregnant women is on the global health agenda, likely because there is still a dearth of studies into how to safely include pregnant women in vaccine trials. Researchers have conducted a double-blind randomized trial for a malaria vaccine candidate that included 18 women in France and 50 women in Burkina Faso, none of whom were pregnant.

If a malaria vaccine for pregnant women does eventually get the green light, several big questions remain; Will pregnant women in endemic areas get it? Who will bear the cost of access and distribution?

Atinuke says even if the vaccine is available to pregnant women, she is certain there will  be significant hesitancy when it comes to taking the vaccine. “Trust me, anything that has vaccine in it, I’m sure pregnant women will not want to take it because they do not want any foreign body in their bodies,” she said, adding, “I think most pregnant women will still prefer to take the antimalaria that is given to them than opt for the vaccine.”

Her intuition is spot on. In a survey of three hundred pregnant women about the pandemic and acceptance of future COVID-19 vaccination, just over one third (37%) said they intended to take the vaccine if it was recommended for pregnant women. Reasons for not wanting to take the vaccine ranged from lack of data about the vaccine’s safety for pregnant women and possible harm to the fetus, according to the report. Will a malaria vaccine trigger a similar response from pregnant women?

Another salient issue is the cost of ensuring that vaccines get to the people who need them most. Next steps for the WHO-recommended malaria vaccine for children will include funding decisions from the global health community for broader rollout, and country decision-making on whether to adopt the vaccine as part of national malaria control strategies. Assuming that pregnant women in endemic areas are willing to take a malaria vaccine designed for them, will development partners be willing to support the cost and distribution of a malaria vaccine for pregnancy?

While global health experts continue to grapple with these questions, continued efforts should focus on eliminating malaria in endemic areas. The CDC notes that eliminating malaria in the US “consisted primarily of DDT application to the interior surfaces of rural homes or entire premises in counties where malaria was reported to have been prevalent in recent years. By the end of 1949, more than 4,650,000 house spray applications had been made. It also included drainage, removal of mosquito breeding sites, and spraying (occasionally from aircrafts) of insecticides. In 1949, the country was declared free of malaria as a significant public health problem.”

In June 2021, China officially eliminated malaria, to become the first country in the “WHO Western Pacific Region to be awarded a malaria-free certification in more than 3 decades,” according to the WHO. Success factors for China’s journey includes the provision of a free basic health care package for residents, effective multi-sector collaboration, and strict adherence to a 1-3-7 strategy for reporting, confirming, and preventing further spread of malaria cases. The country has also increased surveillance in at-risk zones to prevent the re-establishment of the disease.

While the world waits for the malaria vaccine for pregnant women in endemic areas, these success stories offer the continued possibility that malaria can be eliminated as a public health burden.

Atinuke has continued to protect herself and her baby with existing preventative measures. She says when a malaria vaccine is available, she is willing to take it. “I’m willing to take (the vaccine) if the WHO recommends it and my doctor recommends it, because I know that malaria can be deadly for both the pregnant woman and her baby. So, anything to protect myself and my baby, I’m happy to do it,” she said.