14 DAY TRIAL // The second-largest pharmaceutical company in the world – Merck, has developed an experimental vaccine against Staphylococcus aureus, which proved to be very well-tolerated and to stimulate antibodies, the American Society for Microbiology reports.
S. aureus is the most frequent cause of hospital-acquired infections, and the multidrug-resistant strain of S. aureus is an ever increasing problem.
Clayton Harro of the Johns Hopkins Bloomberg School of Public Health, Baltimore, and the lead investigator on this study, said that “invasive S. aureus infections (blood stream, deep wound, prosthetic device) have high associated morbidity and mortality.”
In the United States and in Europe, 6 million people become infected every year and 140,000 of them die.
For the study, the researchers gave a single vaccination in one of three different doses, or placebo, to four groups of 31 healthy volunteers (18 to 55 years old), each.
All three doses triggered a rise in antibodies – the two higher doses far more so than the lowest dose, and antibody levels rose significantly after almost two weeks, and stayed this way even after three months.
Harro said that “based on this and other studies, the vaccine is now being tested in people who are at high risk of getting infected by S. aureus to see if the resulting antibodies can protect them from disease.”
The success of such a vaccine is critical and designing it has been a real challenge, the researchers said.
“S. aureus has a complicated structure, a vast array of strains, and an uncanny capacity to evade immune surveillance systems in our bodies,” added Harro.
The development of this experimental vaccine has been possible after the researchers discovered a single protein on the bacterial surface that is common to most Staphylococcus aureus strains.
This discovery was made through modern antigen discovery techniques, that have not been previously available.
The study presenting the vaccine research has been published in the Clinical and Vaccine Immunology journal.