Health officials are investigating an outbreak of meningococcal disease in Kent after two young people died and others remain seriously ill.
The issue was raised during Prime Minister's Questions, where Labour leader Sir Keir Starmer expressed sympathy for the families and said public health teams are tracing close contacts, distributing antibiotics and preparing a targeted vaccination campaign.
Authorities say there is a risk that people incubating the infection could have travelled elsewhere, and that secondary cases are possible.
Experts are still determining how widespread the specific strain is and whether it behaves differently from past strains.
Professor Hunter said the UK Health Security Agency is following established guidance on managing clusters of invasive meningococcal disease.
For now, officials judge the chance of a large-scale spread to be low, though investigations continue.
Meningococcal infection can cause meningitis, septicaemia (blood infection), or both.
Bacteria that invade the protective membranes around the brain can also enter the bloodstream, triggering a severe, body-wide reaction that can damage organs and be life-threatening.
Early signs often resemble a bad flu and can come on quickly.
Look out for high temperature, vomiting, headache, muscle or joint aches, cold hands and feet, and an unusual or persistent tiredness.
Symptoms more specifically linked to meningitis include extreme drowsiness or difficulty waking, a very stiff neck, severe headache, vomiting, sensitivity to light, confusion and seizures.
Signs that suggest septicaemia include fever with shivering, intense pain in the limbs or joints, very cold extremities, pale or blotchy skin, fast breathing, stomach cramps or diarrhoea, and a rash that may be red or purple and does not fade when pressed.
Difficulty standing or a reduced level of consciousness are also warning signs.
Not everyone will show every symptom and they can appear in any sequence.
Health services urge anyone worried about these signs to seek urgent medical attention, because rapid treatment can be lifesaving.
