What happened in the past few days is lending credit to expert warnings of the danger of a potential "second wave" of novel coronavirus infections, reminding us of the critical need of balancing the needs for "normalcy" and prudence.

After 35 consecutive days of zero new infections, Wuhan, capital of Hubei province, diagnosed six new cases on May 9 and 10, all from the same neighborhood. 

There are no clear clues as to how the latest cases arose, and a panel of medical experts has said they are probably attributable to past cases in the neighborhood. Nonetheless, the pandemic alert level for the neighborhood has been raised from low to intermediate.

With heightened vigilance and corresponding responses in place, very likely conditions in this closely watched new hot spot will not get very bad. 

But the appearance of a few such clusters of infections in recent days highlights that counter-epidemic measures cannot be relaxed yet.

Which is why National Health Commission spokesman Mi Feng said at a media briefing that although the situation has normalized, the prevention and control efforts cannot be eased yet. 

And why all residents in Wuhan are to be tested for the virus over the coming days, according to reports.

The potential risk of a second wave of infections was underscored by the Republic of Korea announcing its biggest cluster of new infections for more than a month. 

The important message sent by these new infection clusters is that despite the achievements that China and some other countries have made to date in curbing transmission of the virus, that success remains fragile, and will perhaps prove to be elusive if precautions are relaxed too hastily.

Although the governments of many countries are taking tentative steps, or recklessly bold strides in the case of some, toward bringing their economies out of suspended animation by easing the quarantine measures, such incidences show that the restrictions such as social distancing that people have had to grow accustomed to will have to continue, even become part of a "new normal". 

The World Health Organization has urged "extreme vigilance" as countries emerge from their lockdowns, and that is no crying wolf. As WHO officials stressed in an online news briefing on Monday, early studies indicate that the antibody levels to the virus within the general population are lower than expected, meaning that most people remain susceptible to the disease. 

Counting on herd immunity to halt the spread of COVID-19 "is a really dangerous, dangerous calculation", Mike Ryan, head of the WHO's emergencies program, warned. 

Until there is a vaccine — should one be developed — the key to stimulating economies while preventing second waves of contagion is for countries to slowly and steadily lift their lockdowns while remaining vigilant, maintaining surveillance and, when any infections are identified, conducting rapid and rigorous contact tracing to stop the infection clusters growing out of control.