The Ministry of Health has begun an investigation into two cases of the highly infectious whooping cough at a Devonshire school.Carlos Symonds, head of school at Somersfield Academy, told parents in an e-mail yesterday that the department had confirmed that the students who caught the illness had been up to date with their vaccinations.Mr Symonds added: “Given that the vaccinated students still contracted the disease, the efficacy of the dosage, the current strain of whooping cough and immunisation schedules are being carefully reviewed by the Department of Health’s Epidemiology and Surveillance Unit.“Please note that the Department of Health maintains the immunisation records of all children in Bermuda and, while vaccinations are strongly recommended, they are not legally mandated. “As such, while the school collects immunisation records upon entry, proof of adherence to the recommended immunisation schedule has not been a condition of admission or retention.”The school urged parents to remain vigilant about the potential spread of the illness and to contact their children’s doctor if symptoms appear.A spokeswoman for the Ministry of Health said yesterday that it was too early for an official comment, but confirmed the Epidemiology and Surveillance Unit had begun investigations.The Devonshire school warned parents on February 1 that two cases of pertussis — whooping cough — were confirmed in a single primary year group.Whooping cough is spread in the droplets of the cough or sneeze of an infected person and is highly contagious.The first symptoms are similar to a cold, and can include a sore throat, runny nose, and red and watery eyes. Intense coughing usually starts about a week later.Coughing spells can end with the affected person gasping for breath, causing a “whooping” sound.