So far, there has been a total of 160 confirmed cases of Covid-19 in Singapore.

Among this is a supposedly rare instance of a patient, Case 82 who was diagnosed with both dengue and Covid-19 at the same time.

Apart from Case 82, The Straits Times reported that another Covid-19 patient, a 57-year-old male, had also tested positive for dengue.

These two patients were then later found to not have dengue, according to a paper published in The Lancet medical journal on March 4.

Dengue false-positive test

The paper, which is on the false-positive dengue results in the two Covid-19 patients, was published by a group of doctors.

These included doctors from the National University Health System, Ng Teng Fong General Hospital and polyclinics.

According to the paper, the 57-year-old man visited a hospital for fever and cough on Feb. 9, and tested negative for dengue.

As his symptoms worsened, he visited another healthcare clinic and tested positive for dengue.

He was referred to the hospital for dengue, and was subsequently found to have Covid-19.

However, repeated tests for dengue then came back negative, including his original seropositive sample, which led doctors to conclude that the initial result was a false-positive.

Case 82 was also originally admitted to Ng Teng Fong General Hospital as a dengue patient in a general ward on Feb. 15.

She later tested positive for the Covid-19 infection on Feb. 18, and was subsequently transferred to an isolation room.

When doctors repeated a dengue test on her, it returned a negative result.

An earlier blood sample also tested negative.

Implications for public health

In their paper, the authors wrote that failing to consider Covid-19 because of a positive dengue test has "serious implications" for public health.

These cases highlight the importance of recognising false-positive dengue serology results in patients with Covid-19, they added.

They wrote:

"We emphasise the urgent need for rapid, sensitive, and accessible diagnostic tests for SARS-CoV-2 (the virus that causes Covid-19), which need to be highly accurate to protect public health."

Top photo via Wikipedia, NCID