The news that a COVID-19 vaccine developed by Pfizer and BioNTech is reportedly more than 90 percent effective has been greeted as a watershed moment in the battle against the pandemic.

But hopes that it heralds a swift end to the global health crisis are probably premature as the claim is based on early and incomplete test results, and final official approval procedures will take time. Even if all the hurdles are cleared and the vaccine is declared good to go, production capacity will determine when it becomes available to the public and how limited the supply will be.

And that is true for other vaccines, including the Chinese one that claims to have the same efficacy.

But if all goes well, it is another sign that the unprecedented efforts to develop vaccines may be bearing fruit, and that will undoubtedly be a positive development.

Until effective vaccines are rolled out on a large scale, however, the only reliable way to stem the spread of the novel coronavirus remains social distancing, mask-wearing and hand-washing. A hygiene regime that needs to be maintained.

Yet even as these keep the virus at bay in China along with effective control of cross-border transmission, cold-chain food imports have attracted unprecedented attention as a channel for infections with the continued spread of the virus overseas.

Responding to warnings about the risks, the State Council has issued a formal protocol for preventive all-around disinfection of imported cold-chain food, which requires "entire-process" "closed-circuit control" and all-around traceability.

Judging from the multiple latest discoveries of the virus on cold food packaging, this is precisely what is needed. On Friday, authorities in Shandong and Shanxi provinces detected the virus on the outer packaging of cold-chain food imported via the Tianjin port. The next day, a loader with a Tianjin-based cold-chain food company was diagnosed with COVID-19.

The findings have put the northern coastal city on a "wartime" footing, and emergency screening is underway in Shandong, Shanxi and Hebei provinces. The idea is cold-chain food imports should not be allowed to become the Achilles' heel of the country's pandemic prevention and control regime.

If earlier alerts regarding cold-chain food imports seemed overblown to some, they obviously do not now. Nine other places across the country have detected the virus in either imported frozen food or on packages since July.

Considering the price the country and its people have paid for the prevention and control of infections over the past months and the hard-earned return to near normalcy they enjoy now as a result, the only way to preserve such achievements is sustained vigilance plus meticulous fence-mending to ensure there are no gaps in the country's defenses.