The most concerning index in Hong Kong today is perhaps no longer the Hang Seng Index, but the “epidemic index” – the number of new confirmed cases of the novel coronavirus contractions. Besides the virus trends in Hong Kong, the statistics released from mainland China is also of high concern to many Hongkongers.
In the beginning of February, the number of confirmed cases of the novel coronavirus in China was on a decreasing trend, which was quite encouraging. However, on 12 February, there was a drastic increase of more than 13,000 new cases overnight! But don’t panic just yet. The surge in the number of confirmed cases was solely because of the widening of the diagnostic criteria to include clinically diagnosed cases.
What is clinical diagnosis?
It is the determination of a diagnosis based on the objective facts (such as travel history to Wuhan), signs and symptoms (such as cough and fever), and other auxiliary tests (such as shadows found in the lungs on computed tomography). In other words, it is a diagnosis made with a patient’s presentation being compatible with the disease but fall short of a laboratory confirmation.
Why change the criteria?
The laboratory diagnosis for coronavirus is done through rapid testing for the presence of virus by real time polymerase chain reaction. In real life clinical situation, it was found that this virus could be quite evasive. In a number of cases, the rapid test was initially negative, and it was not until the second or even the third time that the test turned positive.
The inclusion of clinical diagnosis will allow such patients to be isolated and treated at an earlier stage. Moreover, this will also reduce the number of suspected cases, and better reflect the overall epidemic situation. It is worth mentioning that Hong Kong and most other countries still rely on laboratory confirmation for diagnosis of the noval coronavirus at present, mainly because of difference in severity of the epidemic.
Last but not least, the sharp increase of confirmed cases in China does not mean that the situation has gotten worse. In fact, after a couple of days, the number of new cases reported has fallen back to roughly the same level as before the change in diagnostic criteria.
Dr Alexander Chiu, Medical Director, Health and Employee Benefits, AXA Hong Kong and Macau