The world's first ever vaccine for malaria which is the globe's biggest killer could soon be available after successful human trials.
The revolutionary new vaccine protects adults from infection for more than a year and stops them being carries for the tropical disease spread by mosquitoes.
Just one bite from an infected mosquito bite is all it takes to become infected.
In poorer countries stopping being bitten in the first place by using mosquito nets or insect repellents is the first line of defence.
Until now, uncovering a vaccine for the disease - which effects hundreds of millions of people yearly - had proven difficult.
The World Health Organisation estimates there were 198 million cases of malaria worldwide and 584,000 deaths in 2013.
The complex nature of the malaria parasite meant that despite decades of intense research and developmental effort no treatment was found.
But in a ground-breaking study by the University of Maryland School the vaccine not only immunised people for over a year but also ensured they could not further transmit it.
And giving people it intravenously rather than by injection gave the best protection.
The PfSPZ Vaccine involves introducing live, but weakened, Plasmodium falciparum - one of the parasites that cause malaria in humans into a person's blood.
Associate Professor Dr Kirsten Lyke said: "There results are really important.
"Malaria has such a devastating effect on children, especially in Africa.
"This vaccine has the potential to help travellers, military personnel and children living in malaria-endemic areas."
In the Phase 1 trial - the earliest trials of drugs in people - volunteers were exposed to the malaria-causing parasite P. falciparum.
The parasite is usually transmitted to humans via the bite of infected mosquitoes.
Previous research had shown that the vaccine worked for three weeks after immunisation, however the clinical study analysed its longer term effects.
A total of 101 adults aged 18 to 45 years who had never had malaria took part with 59 given the vaccine while 32 were not vaccinated.
Participants were then exposed to the bites of mosquitoes carrying the same P. falciparum strain from which the vaccine was derived.
Following this, scientists took blood samples from participants to measure parasite levels for evidence of protection.
The study revealed that the vaccine provided protection for up to a year in more than half (55 per cent) of subjects and also provided sterile protection.
It was also found that Intravenous administration provided better protection than intramuscular injection - both in the short and long term.
Long-term protection is crucial for people who are vaccinated but not actually exposed to malaria for months, such as travellers or military personnel.
Durable protection is also important for mass vaccination campaigns aimed at interrupting transmission in places where the disease is widespread.
The vaccine was developed and produced by Sanaria Inc, of Rockville, Maryland, with support from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.
The study was published in the journal Natural Medicine.
Source: The Mirror