Meningitis B vaccines will be offered to year 11 pupils at schools affected by the Kent outbreak.
NHS Kent and Medway said on Tuesday that 10,627 vaccines had been given out.
The meningitis outbreak, which left two dead, peaked on 13 March.
On Monday, 20 cases of meningitis had been confirmed, with a further three under investigation, bringing the total to 23.
This was down from 29 on Sunday, when 20 cases were confirmed, and a further nine were under investigation.
Officials started vaccinating University of Kent students on 18 March.
The following day, on a visit to the campus, Health Secretary Wes Streeting said the programme would be expanded to more people, including sixth form pupils at four schools with known or suspected cases of meningitis B.
Experts at the UKHSA have been investigating the "unusual" outbreak.
They looked at three possibilities: the strain; immunity of the affected population; and social factors.
The UKHSA has stated that "it is highly likely that all three factors are contributing," but that it is a "realistic possibility" that the strain is the "main driver".
Officials confirmed last week the strain behind the outbreak belongs to a group of bacteria known as group B meningococci, with a recently emerged subtype that has been present in England since 2020.
However, the UKHSA suspects the bacteria could have mutated - saying the genome has "multiple potentially significant genetic differences".
The UKHSA also confirmed the people affected have a median age of 19, and while the majority are in education, five are not students.
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Of those affected, 87% attended Club Chemistry in Canterbury at least once between 5 March and 7 March before becoming unwell.
Most of those were students, and the three cases who did not go to the nightclub are all University of Kent students living in halls with links to those who did attend.
Professor Robin May, chief scientific officer at UKHSA, said that "preliminary analysis offers strong reassurance" that existing vaccinations and antibiotic treatment are "effective against this strain".
(c) Sky News 2026: Meningitis B vaccines offered to more school children - as cases fall
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