Over 200 pupils and adults have been vaccinated against hepatitis A, after two more cases of the infection were confirmed at a school in Gelligaer.
Public Health Wales vaccinated 222 pupils and 48 adults associated with Glyn-Gaer Primary School, Gelligaer as a precaution last week.
Along with the six confirmed cases of hepatitis A at the school, two further outbreaks have been confirmed in the local community, and links between the patients and the school are being investigated by Public Health Wales, Aneurin Bevan University Health Board and Caerphilly Council Borough Council.
That signifies a double in confirmed cases in just over a week.
Parents of pupils at at Glyn-Gaer Primary School received a letter on Friday April 29 advising them to remain vigilant to the signs of hepatitis A, as children exposed to the infection may still develop symptoms.
Heather Lewis, Consultant in Health Protection for Public Health Wales, said: “Hepatitis A is a viral infection, usually short lived that has unpleasant symptoms but is rarely serious. Children often only have a very mild illness.
“Symptoms can include flu-like symptoms such as tiredness, general aches and pains, headaches and fever, as well as loss of appetite, nausea or vomiting, abdominal pains, jaundice, very dark urine and itchy skin.
“Good hand washing after using the toilet and before preparing or eating food is the best way to prevent the virus spreading.
“Children may have very few symptoms but can pass the virus onto others so we are reminding parents to encourage good hand washing at all times.
“Parents are also being advised not to send their child to school for 7 days if hepatitis A is suspected.
“We are confident that to date, all the public health actions needed to control this outbreak have been taken and that the risk to the public remains low. However, due to the very long incubation period of hepatitis A we may see more cases.
“We continue to work closely with Environmental Health Officers to investigate this outbreak and to offer advice to parents, school staff and pupils.
“People are advised to contact their own GP or NHS Direct Wales on 0845 46 47 if they have any concerns about their health or their child’s health.”
Hepatitis A vaccination is not routinely offered on the NHS as the infection is rare in the UK, with only 13 reported cases in Wales in 2012.
Further information about hepatitis A is available on the Public Health Wales website at http://www.wales.nhs.uk/sitesplus/888/page/43692.