A college student has died and two people are being treated after cases of meningitis in Reading, Berkshire, the UK Health Security Agency (UKHSA) said.
It said close contacts of those affected were being offered antibiotics as a precaution.
The agency said the person who died was a student at Henley College, in Henley-on-Thames, Oxfordshire, and it was sharing information about the infection with students and parents at all affected schools. It added the risk to the wider public was low.
The UKHSA said one case had been confirmed as Meningitis B (MenB) and it was awaiting further testing results. It has not said what the link to Reading was.
The Hart Surgery, a GP practice in Henley-on-Thames, said it was in contact with the UKHSA due to the college's location, adding the agency was "actively contacting those who may be at risk due to a close association with the student involved".
But it said anyone who had not been contacted by the UKHSA did not need any treatment. Students and staff can attend the sixth form college as usual.
"The number of confirmed cases is very low so there are currently no plans for a local emergency meningitis vaccination programme," it added.
Henley College has yet to comment.
Two months ago, two people died after an outbreak of MenB in Kent, linked to a nightclub in Canterbury, and, in April, three young people contracted meningitis in Dorset.
Dr Shamez Ladhani, consultant epidemiologist at the UKHSA, told the BBC it was "really unfortunate" to have had three separate outbreaks in such a short space of time.
"This is a very rare disease but when it strikes it can be very lethal," Ladhani said.
"We have the strain from one of the three cases [in Reading] and we know that it is completely distinct to the one that caused the outbreak in Kent and the one that caused the outbreak in Dorset.
"We have identified a social network where these three are connected and we are almost certain that this is going to be the same strain.
"The fact that they have the infection means that we have the same preventative measure and will try and identify the contacts and protect them with antibiotics and vaccines."
Ladhani told BBC Radio 4's Today programme it was an "evolving situation".
"Just like Kent was, just like Dorset... it is difficult to know where it is going to go from here," he said.
"Hopefully it will settle down. At the moment, every indication is that there is no increased risk to any of the students in Reading, but the situation is evolving and if that changes we will take action if needed."
There are about 300 to 400 cases of meningococcal disease diagnosed in England every year.
It is most common in babies, young children, teenagers, and young adults.
Meningitis symptoms can develop suddenly - and can include:
Henley College is a sixth form which offers more than 60 A-Level, T-Level and vocational diploma courses to 2,000 full-time students drawn from 100 schools in Berkshire, Buckinghamshire and Oxfordshire
Freddie van Mierlo, MP for Henley and Thame, said: "My thoughts are very much with the family and friends of the students affected.
"I would urge everyone in the area to follow the medical advice and in particular to re-familiarise themselves with the symptoms, as well as check their vaccination history."
Reading University has confirmed that there are no reported cases among its students.
Dr Paddy Woodman, director of student services said: "I was deeply saddened to hear this news and my thoughts, and those of the whole university community, are with their family and friends.
"We will be contacting students to remind them of existing information about looking out for signs of meningitis, and the importance of acting immediately on any worrying symptoms, as well as checking their vaccination status."
The UKHSA said young people should check they are up to date with vaccinations, including the MenACWY vaccine offered to pupils in Years 9 and 10.
It remains free on the NHS for people until the age of 25 but does not protect against all strains of meningitis.
The UKHSA said other strains, like MenB, can circulate among young people.
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