Queensland researchers have developed an experimental vaccine against a “nasty” virus that can cause severe disabilities and sometimes death in unborn babies.
Key points:
- Scientists hope to carry out human trials of the experimental vaccine by 2024
- Adolescents would be the initial target population if the vaccine was successful
- CMV can be very harmful to an unborn baby if their mother contracts it
The vaccine, which the QIMR Berghofer Medical Research Institute is heralding as a breakthrough, is designed to protect against cytomegalovirus (CMV), which can result in babies developing hearing loss, cerebral palsy, developmental delay and other severe disabilities while in the womb.
Scientist Rajiv Khanna has been working on the vaccine for 15 years.
He hopes to conduct human trials by 2024 and is in discussions with potential industry partners to progress the vaccine.
Professor Khanna said the vaccine worked by mounting a two-pronged immune-system attack against the virus, deploying both antibodies and killer T cells.
“A major reason for vaccines not working for CMV is that most of the previous vaccine formulations have tried to control the virus through … antibodies alone,” he said.
“We’ve learned that antibodies alone are not sufficient. These viruses very cleverly hide inside the cell. And to kill that virus, which is inside the cell, you need killer T cells.
Professor Khanna said the vaccine had produced a strong and sustained immune response in mouse trials.
“The longevity of the immune response is very critical,” he said.
Virus most dangerous for unborn babies
Adolescents would be the initial target population if the vaccine was successful, but it could also benefit people across their life span.
“If you don’t have a pre-existing immunity to this virus and you get exposed during pregnancy … you have a one in three chance of transmitting that virus to the baby through the placenta,” Professor Khanna said.
“But if you’re actually immune, then that chance goes down to one in 100, even lower.”
The virus can also cause serious problems in organ-transplant patients and has been implicated in some brain tumours.
CMV is a herpes virus carried by an estimated 50 per cent of the population. Most people will never develop symptoms and a small proportion will experience a glandular fever-like illness.
But if women acquire the virus during pregnancy, it can be potentially dangerous to their unborn child.
“It’s a pretty nasty disease once it gets into unborn babies,” Professor Khanna said.
Brisbane mother Miff Ward had not heard of CMV until she learned she was infected while pregnant with daughter Azaria, who was born with permanent hearing loss.
“It was a really difficult and emotional time for us,” Ms Ward said.
“It’s surprising that there is so little awareness of such a common virus that can cause so much damage to an unborn baby.
“I’m really excited to learn that a vaccine may be coming … We were lucky that the effects of CMV were not more severe considering what can happen.”
CMV is most commonly spread through saliva and other bodily fluids.
Pregnant women are urged to practise strict hygiene, particularly when changing nappies, wiping a child’s nose or when in contact with urine.
They should not share a toothbrush with a child and avoid contact with saliva when kissing children.
Professor Khanna said even if the CMV vaccine was successful, it would realistically undergo years of human trials before it became available to the public.
He said Queensland had the capability to manufacture the vaccine.