The Institute of Medical Research (IMR) has been tasked to study the bacteria from the diphtheria patients thoroughly to ascertain why some people who are vaccinated still get the disease, said Health Minister Datuk Seri Dr S.Subramaniam.

He said as of Friday, there were 26 diphtheria cases with the latest, two of the Health Ministry staff found positive in Negeri Sembilan.

"Doctors must be vigilant with patients with sore throat who are not getting better. The patients must be sent to the hospitals so that they can start treatment early," he told reporters here Friday when asked on the latest
information on diphtheria.

Until Friday, diphtheria has recorded five deaths.