Singapore's Ministry of Health (MOH) said on Thursday that it has screened all the 48 close contacts of the Bangladeshi worker, who died of diphtheria on Aug 4, and all of them have tested negative for toxigenic Corynebacterium diphtheriae.
Last week the ministry had said that the 21-year-old worker was likely to have been infected in Singapore as he had not travelled out of Singapore recently.
MOH said that the close contacts were screened and as of 5 pm on Aug 8, two of them had developed sore throat since Aug 3. They were warded in Khoo Teck Puat Hospital have been discharged. However, the rest of the 46 people are all well.
"All 48 contacts have been given preventive medication and a booster diphtheria vaccine. There is no evidence of further spread," the ministry told Channel NewsAsia.
MOH added that the vaccination against diphtheria is effective in reducing infection and severity of the infection. In Singapore, compulsory vaccination is established as part of the National Childhood Immunisation programme.
According to the 2010 National Health Survey, 92 per cent of adult Singapore residents aged 18 to 79 have some immunity to diphtheria. "As such, cases of diphtheria are rare in Singapore and the threat of spread is low," MOH added.