GSKThe World Health Organization (WHO) has awarded prequalification to GSK’s (LSE/NYSE:GSK) Mosquirix.

The move marks the first time that a malaria vaccine has won prequalification.

The WHO decision regarding the Mosquirix malaria vaccine is a prerequisite for United Nations (UN) agencies like UNICEF to procure the vaccine in regions with moderate to high P. falciparum malaria transmission.

Malaria was associated with 409,000 deaths in 2019, according to WHO.

GSK shares fell 1.19% in afternoon trading to $31.47.

The Mosquirix malaria vaccine is also referred to as RTS and S/AS01.

Mosquirix has a long developmental history. GSK began developing the vaccine, then known as RTS,S, in 1987.

In 2001, GSK and PATH’s Malaria Vaccine Initiative entered into a public-private partnership to develop the vaccine for infants and young children in malaria-prone countries.

To win the WHO prequalification, GSK shared detailed clinical, safety and technical data related to the Mosquirix vaccine.

“WHO prequalification of Mosquirix is a key step in reaching children with the first and only approved malaria vaccine,” said Thomas Breuer, chief global health officer at GSK. ”

More than one million children in Ghana, Kenya and Malawi have received at least one dose of the vaccine.

Data from those three countries support the vaccine’s safety profile.

GSK has a technology transfer program for the vaccine with Bharat Biotech of India.

WHO has advised that eligible children at least five months old receive a schedule of four malaria vaccine doses.

The vaccine has been profiled in The Lancet and on ClinicalTrials.gov. The Lancet article noted that the vaccine “prevented a substantial number of cases of clinical malaria over a 3–4 year period in young infants and children.” In addition, the article found the vaccine effective when provided with or without a booster dose.

In 2015, the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) adopted a positive scientific opinion of the vaccine in children between 6 weeks and 17 months.