COVID-19 persists: Current risk of a recurrence of the epidemic in China.

Dear Editor

In December 2019, nearly a month before the traditional Chinese Spring Festival, the first confirmed case of novel coronavirus pneumonia (subsequently named coronavirus disease, COVID-19) appeared in Wuhan, Hubei Province, China, and subsequently spread to other cities with the flow of people during the Spring Festival. On January 20, 2020, after a field investigation in Wuhan, Zhong Nanshan, head of the high-level expert group of the National Health Commission of China (NHCC), confirmed that there was human-to-human transmission of COVID-19 (http://www.xinhuanet.com/politics/2020-01/20/c_1125487200.htm), and subsequently the COVID-19 outbreak quickly became the focus of media worldwide, attracting widespread attention.1, 2, 3 As of December 6, 2021, COVID-19 had spread to about 207 countries with 265,194,191 cases reported worldwide. Some countries have experienced multiple epidemic waves. Despite containment measures taken by national authorities and the international community, the COVID-19 pandemic remains severe. In order to effectively contain the spread of the epidemic, the Chinese government has introduced measures such as lockdown of cities at high risk of COVID-19 epidemics, quarantine, nucleic acid screening, free COVID-19 treatment, mask wearing, regular disinfection, and COVID-19 vaccination. Due to the joint efforts of the Chinese government and the whole nation, the COVID-19 epidemic in China has been gradually contained, with the number of large-area, concentrated outbreaks dropping gradually. However, due to the high number of COVID-19 cases worldwide and the approaching of the traditional Chinese Spring Festival, China still faces a risk of a recurrent COVID-19 epidemic, thereby making vigilance a necessity.

We analyzed the number of confirmed cases and deaths of COVID-19 in China in the past 1 year according to the COVID-19 case data released by the World Health Organization (WHO), and observed that there were two distinct peaks of cases in China in the past year, with the number of weekly confirmed cases being up to 1306 at the first peak and 4051 at the second peak (Fig. 1 ). According to the data released on the National Health Commission (NHS) website, we analyzed the geographical distribution of confirmed cases in the past 1 year and observed that regions with close international exchange and cooperation, such as Taiwan and Hong Kong, had a relatively high number of confirmed cases (16,011 and 6223, respectively). Moreover, there was a relatively high number of cases in border cities, such as the those in Yunnan(1523), Heilongjiang (1075) and Inner Mongolia (655); as well as in coastal cities, such as Shanghai (1552), Guangdong (1335), Jiangsu (939), and Fujian (836) (Fig. 2 ), indicating that importation from outside the country is currently the main reason for the increase of cases in China. The number of cases in some densely populated cities such as those in Hebei Province, Sichuan Province, and Henan Province were 1085, 471, and 348, respectively, which were significantly higher than those in less densely populated areas such as those in Xinjiang (1) and Tibet (0) (Fig. 2), suggesting that dense population and high human flow are also important reasons for the COVID-19 outbreaks.

Fig. 1

Number of new confirmed cases and deaths of COVID-19 in China from November 30, 2020 to December 6, 2021. The official statistics for all documented cases of COVID-19 in China were obtained from the WHO (https://covid19.who.int/region/wpro/country/cn).

Fig. 2

Geographical distribution of confirmed cases of COVID-19 in China. A. Geographical distribution of current confirmed cases in China as of December 6, 2021; B. Cumulative number of confirmed cases in China from November 30, 2020 to December 6, 2021.The official statistics for all documented cases of COVID-19 throughout China were obtained from the NHS (http://www.nhc.gov.cn/xcs/xxgzbd/gzbd_index.shtml).

Although the epidemic has been effectively contained in China, the country still faces several risk factors that could cause a recurrence of the epidemic around the time of the Spring Festival: (a) the Spring Festival is a traditional festival in China, and most people reunite with their families during this period, which increases the risk of epidemic spread; (b) the cold climate with low temperatures during the winter increases the risk of COVID-19 infection; (c) the persistence of foreign epidemics and the fact that China is a major importer/exporter country may result in imported infections; (d) the emergence of new mutant strains increases the difficulty of prevention and containment of COVID-19, and the original vaccine may not achieve complete protection against emerging strains, so booster vaccination is needed to maintain the level of immunological protection in the population; (e) China has continued to promote vaccination, and the current vaccination rate has reached approximately 78%, but the majority of the population have not received a booster vaccination does against variant strains and the vaccination rate among children is low; (f) after the long against the COVID-19 epidemic, vigilance among the general public has waned, and mask-wearing and disinfection measures have become less frequently observed. Given the above risk factors, it is clear that care should be taken in China for preventing and containing COVID-19 outbreaks. The government should be more vigilant and should strengthen prevention and containment measures for avoiding new COVID-19 outbreaks, while minimizing economic losses. Additionally, other countries are encouraged to learn from China's example of effective measures for COVID-19 prevention and containment, so as to overcome the COVID-19 pandemic as soon as possible.

Declaration of Competing Interest

None.