Covid-19 Mistaken For Dengue Twice, Has Serious Implications For Public Health

Despite it spreading rapidly around the world, Covid-19 is ultimately still a relatively new disease, and medical experts are still seeking to understand more about it.

Adding to the confusion is the recently published report that its symptoms have been mistaken for that of other diseases.

This worrying revelation emerged when 2 patients in Singapore initially tested positive for dengue, only to be diagnosed with Covid-19 after that —  and they then both tested negative for dengue.

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False positive dengue test may mean Covid-19 is not considered

It’s vital to recognise that patients with Covid-19 may get a false positive when tested for dengue, said a paper written by doctors from the National University Health System, the Environmental Health Institute, Ng Teng Fong General Hospital and polyclinics.

This is because a positive result for dengue may lead to the healthcare authorities wrongfully discounting Covid-19 as the cause of the patient’s symptoms, and treating him as a dengue patient.

That may mean that he is not isolated in the way that Covid-19 patients should be, and may infect others.

In the paper, which was published in The Lancet medical journal on 4 Mar and quoted by The Straits Times, the doctors also warned:

Failing to consider Covid-19 because of a positive dengue rapid test result has serious implications not only for the patient but also for public health.

First woman was previously reported to have both diseases

The first patient, a 57-year-old woman, was previously reported to be the first person diagnosed with both dengue and Covid-19.

She went to a hospital on 13 Feb, complaining of cough, fever, diarrhoea and muscle pain. She tested positive for dengue, but was discharged as an outpatient.

On 15 Feb, her symptoms worsened, and she was warded at Ng Teng Fong General Hospital — but as a dengue patient.

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It was only when she reported breathing difficulties on 18 Feb that she was tested for Covid-19 — and she tested positive.

Doctors then tested her for dengue again, and this time it came out negative.

The Ministry of Health said on 20 Feb that the woman was not diagnosed wrongly, and the results of lab tests and her symptoms had pointed to dengue.

Man tested positive for dengue on the 2nd try

The other patient, a man who is also 57, visited a hospital on 9 Feb, suffering from symptoms including cough and fever. He turned in a negative test for dengue and was discharged.

When he got worse, he went to a healthcare clinic and was tested for dengue again. This time, he tested positive and was sent to a hospital for dengue treatment.

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He later tested positive for Covid-19. After that, he was tested for dengue again many times, but the tests were all negative.

Difference between dengue & Covid-19

In the paper, the doctors outlined a simple test that may help to distinguish dengue sufferers from Covid-19 patients.

Dengue sufferers will usually have a fever and a rash, but they will not have respiratory symptoms, including a runny nose, cough or sore throat.

Covid-19 patients, on the other hand, will present with such respiratory symptoms, they said.

The doctors also urged for competent tests for Sars-CoV-2, the coronavirus that leads to Covid-19, saying:

We emphasise the urgent need for rapid, sensitive and accessible diagnostic tests for Sars-CoV-2, which need to be highly accurate to protect public health.

Could patients have been diagnosed with Covid-19 sooner?

It seems like just when we think our medical authorities have got it covered in terms of testing for the disease and treating the infected, Covid-19 throws us another curveball.

The news that Covid-19 patients have gotten a false positive for dengue, and thus gone undiagnosed for Covid-19 for a longer time, is disquieting. One wonders how many other people have gone undiagnosed for Covid-19 for a long period of time.

All we can do is hope that doctors keep the latest information in mind, and an accurate test for Covid-19, or even a vaccine, is made widely available soon.

Featured image from Facebook and hok.com.