Too many children in the isles have been left unprotected against whooping cough, NHS Shetland has warned.
An increase in whooping cough cases have been reported across Scotland, with several cases confirmed in the isles.
The rise has co-incided with a drop in the number of children who are vaccinated against the condition.
Up-take of the so-called 5 in 1 vaccine offered to babies at two, three and four months of age has dropped from the traditional 95 to 100 per cent in recent years to below 80 per cent now.
The vaccine also protects against diphtheria, polio, Haemophilus influenzae type b and tetanus. Children should have a booster dose as part of their pre-school booster when they are three.
Health officials say whooping cough, also known as pertussis, is very infectious and can cause severe illness in babies and young children, who may need admission to hospital.
Consultant in public health medicine, Dr Susan Laidlaw, warned a number of young children in the isles had been left unprotected from the condition.
“We usually have a good up-take of the 5 in 1 vaccine in Shetland each year, generally between 95 and 100 per cent.
“However in recent years the up-take of the pre-school booster has been low. Recent figures show only 78 per cent of the children who reached the age of five during 2011/12 had received their pre-school booster.
“This means that there are young children, and children going to school in Shetland, who are not fully protected against whooping cough.
“We know that whooping cough is circulating in Shetland and so they are at risk of catching the illness themselves, and also of passing it on to other children – especially babies who have not yet completed all their immunisations.”
Early symptoms of whooping cough are much like an ordinary cold and may include a blocked or runny nose, sneezing, watering eyes, a dry or irritating cough, sore throat, slightly raised temperature and feeling generally unwell.
The early symptoms can last for one or two weeks before progressing to bouts of coughing, though this is not always present.
Adults and older children may have milder symptoms and are less likely to make the characteristic “whoop” sound.
Very young infants may also not make the sound, but bouts of coughing can be followed by difficulty in breathing.
NHS Shetland has urged people showing symptoms to see their GP, and have called for people to exercise a “good cough etiquette” by covering the mouth and nose with a disposable tissue. Children should be helped to do this, too.