Feng Zijian, deputy director of the Chinese Center for Disease Control and Prevention, answered questions about the novel coronavirus epidemic during an interview with China Central Television on Monday night. Below are excerpts from the interview:

Why has the number of confirmed cases of the novel coronavirus increased dramatically?

The sharp increase of confirmed cases has a lot to do with the ability of the coronavirus to spread. Currently it seems that human-to-human transmission is getting stronger.

Another factor contributing to the rocketing number of infections lies in the timing of the epidemic outbreak, which happened in early December. As the Spring Festival travel rush kicked off less than a month later, people in areas with severe infections traveled nationwide, which accelerated the spread of the disease.

Wuhan, Hubei province, the epicenter of the outbreak and with a backlog of suspected cases, has seen especially rapid growth of confirmed cases due to the recent centralization of diagnosis.

Why did the number of confirmed cases surpass that of severe acute respiratory syndrome in a shorter time?

The research shows that human-to-human transmission of the novel coronavirus is similar to SARS, which means that a patient can infect two to three people on average.

However, the doubling time of the novel coronavirus is shorter than that of SARS. Compared with nine days to double the number of infected cases in terms of SARS, it only takes about six or seven days for the novel coronavirus.

Are the changes in the novel coronavirus the reason for the increase in infected children?

The increase in child cases might be related to the various chances of human exposure. People at different ages are all susceptible to the new respiratory pathogen. But the chance of exposure may vary due to different ages, and so does the incidence.

It's observed that the symptoms of the pneumonia disease seem to be less severe in a child than an adult. No critical conditions have been reported in child cases.

Will there be another outbreak period of the novel coronavirus in the future? When can the epidemic be basically controlled?

It is very difficult indeed to predict the epidemic trend at present. With multiple measures having been taken, we will effectively control the spread of the coronavirus. But we can't have high hopes it will be done in a week.

We must continue to strengthen prevention and control measures and step up diagnosis and treatment efforts in areas of severe infections, as well as enhance the detection of infected cases in other places. We will also trace people with close contact with patients and put them in medical observation. The epidemic will be brought under control as long as all the measures can be put in place.

What's the point of extending the Spring Festival holiday? Is there a need to further extend it?

It's a very important strategy to control the spread of respiratory infectious disease through human-to-human transmission by reducing the flow of people and personal contact, as well as increasing interpersonal distance. Chinese authorities extended the Lunar New Year holiday as a key measure to control the spread of the novel coronavirus.

The longer the holidays are, the better control of the epidemic will be. But we also have to balance things because people still have to live and work, and emergency materials have to be produced and transported.

On the one hand, we have to take measures to block the spread of the epidemic. On the other hand, we have to minimize the impact on people's lives, as well as social and economic impacts.