Public Health South will review all recent cases of the meningococcal B New Zealand strain in the southern area to try to identify a cause for the recent spike in the disease.
There have been 12 confirmed cases of the meningococcal B strain in the area encompassed by the Southern District Health Board this year.
Seven of those cases were the New Zealand epidemic B strain, which was targeted by a vaccination programme from 2004 to 2006.
Cases of meningococcal disease in 2016 were almost double the average from 2007 to 2015, in the SDHB area.
The most recent case was Bella Berry, a pupil at Mount Aspiring College.
Another Mount Aspiring College pupil, Christy Facer, was also infected with meningococcal disease, although the strain is not known.
Both girls are expected to make a full recovery.
Medical officer of health Dr Naomi Gough said Public Health South would look at each case for similarities to identify people at higher risk of contracting the disease.
A more detailed review of the seven cases had started, as health officials tried to determine the reason for the spike, Dr Gough said.
Health officials would continue work with Mount Aspiring College to help the school get back to running as usual, she said.
Until the risk of a further case returned to background levels, people still needed to be vigilant about the symptoms of meningococcal disease.
A Public Health South spokeswoman said health officials were not ready to say when the risk would return to such levels.
In an email, a spokesperson for the Ministry of Health said a vaccine for the New Zealand B strain would be considered if it was determined there was an outbreak of the disease.
Working with Pharmac, the ministry was trying to find a source of the vaccine which could be used to stop a potential outbreak.
Many factors were considered when determining the need for vaccination such as the number of cases, population size, time between cases, whether strains were identical and if the vaccine could be used to control an outbreak of a specific strain, the spokesperson said.
