‘Boosting mothers’ malaria immune response can protect infants’

Vaccinating mothers during pregnancy can be an effective strategy for protecting infants from malaria because young children are at the highest risk of dying from infectious diseases such as malaria, a new study has found.

The study, ‘Mother-Newborn Pairs in Malawi have similar antibody repertoire to diverse malaria antigens’, published recently in the Clinical and Vaccine Immunology provides evidence that protection against malaria can be transferred from pregnant woman to their newborn

The study was conducted at University of Malawi’s College of Medicine (CoM) and the University of Maryland, United States (US).

Globally, 2.6 million stillbirths occur each year but it is unclear how many are caused by malaria in pregnancy.

Here in Malawi, malaria is a major public health concern, especially among pregnant women and children under the age of five.

It is also a leading cause of morbidity and mortality, accounting for one-third of all outpatient visits and more than a third of visits among children under five years old.

Malaria in pregnancy is caused by a plasmodium parasite which can have detrimental outcomes to mothers and their babies.

During pregnancy, the woman’s antibodies pass from her blood into the foetus, through her placenta thereby providing some protection against infection at birth.

“We showed that the mother passed antibodies against a whole range of malaria proteins to her infant across the placenta.

“Having antibodies ready to fight all of the different parasite protein types [known as surface antigens] that infants might encounter is important for protecting against malaria infection and disease,” says Mirriam Laufer, researcher and associate professor of paediatrics and director, Division of Malaria Research, Institute for Global Health, University of Maryland School of Medicine.

In the study, the investigators assayed serum from 33 mothers at delivery, and cord blood from their infants between 2013 and 2014.

Researchers ran the serum or plasma from the mothers and the cord blood from the infants on a specially designed protein microarray that allowed them to see if the antibodies responded to different versions of the proteins that malaria expresses.

According to the study, researchers used ultrasounds to assess the age of pregnancy, and followed those whose pregnancies were 20-26 weeks through delivery.

Co-author of the report, Dr. Titus Divala, who is also a researcher with Malaria Project at CoM, says the findings have widened possibilities for vaccinologists, as they can now start thinking of infant-targeting vaccines that can be delivered via the mother or indeed vaccines that can protect both mothers during pregnancy-a period of heightened risk-and their infants.

“This evidence is critical at this stage when the world is focused on finding vaccines against malaria. The only registered malaria vaccine, the RTS,S has not demonstrated much protection for infants as it has in children,” he says, adding that the strategy has worked for other vaccines, such as tetanus.

The researcher says due to conducive weather conditions, presence of the deadliest of the malaria causing parasites, and its vector, sub-Saharan Africa shoulders 90 per cent of the global malaria cases, and the disease is a huge burden on the already constrained national health systems, families and a threat to economic development.

“[Hence] the results of this study will facilitate ongoing malaria vaccine development efforts.  Vaccines are one of the greatest medical interventions ever developed, they often display the best value for money and do save a lot of lives for little effort.  Finding an effective malaria vaccine that protects women and infants will perhaps be the best news to sub-Saharan Africans in ages,” says Divala.

Researchers say malaria research can play a vital role in addressing the malaria burden in Malawi.

So far, an organised approach in addressing malaria in Malawi started in 1984 by the establishment of the National Malaria Control Programme.

Professor Stephen Rogerson, who has worked on various malaria research projects with the Malaria Project in Blantyre but also teaches at The University of Melbourne, says studies carried by Dr. Laufer and her team of researchers can open opportunities for further research, as a breakthrough in future malaria vaccine, would certainly help babies grow better in the womb and be less likely to be born prematurely.

“This would possibly decrease their chances of getting malaria in early life and help prevent malaria in kids, including the terrible number of deaths from severe malaria we see in countries like Malawi,” Rogerson says.

Seven months pregnant Rose Manda, from Mbayani Township in Blantyre says women are currently burdened with sick children especially infants due to high malaria cases at birth.

“At birth young children are prone to fall sick from malaria. A way to reduce malaria cases in infants can reduce the burden that women shoulder after giving birth,” she says. n

*Article produced with support from Scidev.Net.