A cough that lasts longer than two weeks is likely linked to the presence of certain antibodies, according to a new study.

Key points:The study found that patients who had a cough lasting more than two months were more likely to have a weakened immune systemThe study was based on a large study of cough patientsThe researchers said it is too early to tell if the antibodies would be protectiveThe researchers also found the cough was more likely if it was chronic, a condition that is associated with weakened immune systems.

The researchers found that people who had the cough lasting two to three months were three times more likely than the rest of the population to have antibodies in their system, which could lead to a weakened immunity.

“This is the first study that has looked at this question, and it shows that people with a cough that persists for longer than a year are more likely and likely to be weakly protected,” Professor Chris Ritchie, who led the study from the University of New South Wales, said.

“If they have weak immune systems, they could also be vulnerable to new viruses and new infections.”

The study has been published in the prestigious medical journal The Lancet.

The study involved more than 2,000 people in the New South Welsh region who had been coughing for more than three months.

It was conducted by the National Centre for Immunisation and Respiratory Diseases at the University’s Centre for Molecular Medicine, and involved the use of a large-scale blood test.

It found that those who had an allergy to the proteins that produce cough suppressor antibodies were three to four times more at risk of developing the condition.

“The antibody response is the same whether it’s a chronic cough or not,” Professor Ritchie said.

He said while the study had not established the link between cough and weakened immune mechanisms, it was a promising first step.

“There are some people who do have a cough, and we think that we have found that it’s the combination of these factors that are most likely to cause the weakened immune response,” he said.

The research was funded by the NSW government, the NSW Government Health Program and the Queensland Government’s Public Health Program.

Professor Ritchie’s team also included researchers from the Australian National University and the University at Adelaide.