The COVID-19 vaccine's protection can last for more than half a year at least, said Zeng Yixin, deputy head of the National Health Commission, at news conference in Beijing on Dec 19.

He said the estimate is based on follow-up visits to No 3 People's Hospital of Shenzhen, Guangdong province.

Six months after their recovery, 96 percent of people who had been infected with the novel coronavirus still had antibodies to protect them against new infections, the hospital said.

The follow-ups involved 506 people who had recovered from the infection between January and May.

The longest duration of for positive antibodies in this group was more than 10 months, the hospital said.

The purpose of the follow-up visits was to get an idea of how long the COVID-19 vaccines would provide protection, and to offer reference points in large-scale inoculation plans.

Zeng said there is no doubt that the protection the vaccines can provide is longer than half a year, as stipulated by the World Health Organization.

Even so, he said, it is still too early to say that the vaccines can realize lifetime protection, or provide five to 10 years' protection.

Follow-up visits to the hospital will last for five years.