The Ministry of Health (MoH) has issued a warning to New Zealand after declaring a national outbreak of whooping cough. A total of 1,315 cases have been reported since the beginning of 2017.
The MoH is encouraging people to be extra vigilant as they gather for Christmas and New Year celebrations, in order to protect young babies.
"Babies under one year old are most vulnerable to the disease and often catch it from older siblings, their parents or family members and friends," says MoH director of public health Dr Caroline McElnay.
Outbreaks of the disease occur every three to five years. New Zealand's most recent national outbreak was between August 2011 and December 2013, with about 11,000 cases.
Three babies and young children died during this period, with hundreds needing hospital treatment.
"Anyone with coughs should be especially careful if they are likely to come in to contact with babies. Most adults don't realise they have whooping cough, but it is incredibly contagious," Dr McElnay says.
"The best way to protect babies is for pregnant women to get their free immunisation against whooping cough between 28 and 38 weeks of pregnancy, and take their baby for their free immunisations when they're six weeks, three months and five months old."
Any siblings should also be up-to-date with their immunisations. Older children receive free boosters at four and 11 years of age.
Whooping cough is less serious in adults, but is harder to prevent for them as immunity wears off over time.