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The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been declared as a Public Health Emergency of International Concern for over three years (1), leading to a combined health and socioeconomic crisis of unprecedented severity (2). Entering 2022, the highly contagious mutant strain of Omicron variants spread rapidly in China (3). In late 2022, the costs of prevention and control of the epidemic became higher due to the rapid spread of the highly contagious Omicron variants (3). To contain the epidemic in a shorter period, minimize the epidemic impact on socioeconomic development and people’s livelihood (3-4), and take into account the highly infectious but less virulent Omicron variants, the high coverage of COVID-19 vaccines, and the significantly improved health literacy of the public (5), Chinese government successively issued the “20 Measures” and “Ten New Measures” to continuously optimize the epidemic prevention and control plan (6). Then, a rapid transmission of Omicron variants happened throughout China.
In the Omicron variants epidemic in China from late 2022, there has been widespread concern about SARS-CoV-2 infections in rural areas (7). Several studies have reported on SARS-CoV-2 infection in rural China (5,8); however, no study has focused on the trends and differences of SARS-CoV-2 infection by region among the general population in rural China during this period of widespread transmission. To address this knowledge gap, national and regional trends of SARS-CoV-2 infection in rural China among the general population were evaluated using data from the National Sentinel Community-Based Surveillance (NSCS) system during this critical period.
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Approximately 90,000 participants in rural China were recruited into the community sentinel surveillance cohort of NSCS. The average daily rate of newly positive SARS-CoV-2 infections was 2.83%, 4.79%, 4.75%, 4.44%, 2.46%, 2.48%, 1.06%, and 0.57%, respectively, in rural China. The daily average newly positive rate in rural China increased from 2.83% in Round 1 (December 16–19, 2022) to the peak of 4.79% in Round 2 (December 20–22, 2022), then decreased by an average of 29.95% (95% CI: 18.28%–39.96%, P=0.002) per round from 4.79% in Round 2 (December 20–22, 2022) to 0.57% in Round 8 (January 10–12, 2023) (Table 1 and Figure 1A).
Rounds Number of people investigated (n) Number of newly positive (n) Daily average newly positive rate (%, 95% CI) Total Round 1 (December 16–19, 2022) 40,112 4,548 2.83 (2.67–3.00) Round 2 (December 20–22, 2022) 80,024 11,495 4.79 (4.64–4.94) Round 3 (December 23–26, 2022) 113,548 21,567 4.75 (4.62–4.87) Round 4 (December 27–29, 2022) 90,468 12,037 4.44 (4.30–4.57) Round 5 (December 30, 2022 to January 2, 2023) 89,392 8,782 2.46 (2.35–2.56) Round 6 (January 3–5, 2023) 83,454 6,214 2.48 (2.38–2.59) Round 7 (January 6–9, 2023) 93,252 3,969 1.06 (1.00–1.13) Round 8 (January 10–12, 2023) 91,792 1,560 0.57 (0.52–0.62) North Round 1 (December 16–19, 2022) 26,008 3,357 3.23 (3.01–3.44) Round 2 (December 20–22, 2022) 33,130 5,246 5.28 (5.04–5.52) Round 3 (December 23–26, 2022) 35,635 4,017 2.82 (2.65–2.99) Round 4 (December 27–29, 2022) 39,755 4,576 3.84 (3.65–4.03) Round 5 (December 30, 2022 to January 2, 2023) 42,168 4,390 2.60 (2.45–2.75) Round 6 (January 3–5, 2023) 37,486 2,621 2.33 (2.18–2.48) Round 7 (January 6–9, 2023) 42,586 1,618 0.95 (0.86–1.04) Round 8 (January 10–12, 2023) 42,586 627 0.49 (0.42–0.56) South Round 1 (December 16–19, 2022) 14,104 1,191 2.11 (1.87–2.35) Round 2 (December 20–22, 2022) 46,894 6,249 4.44 (4.26–4.63) Round 3 (December 23–26, 2022) 77,913 17,550 5.63 (5.47–5.79) Round 4 (December 27–29, 2022) 50,713 7,461 4.90 (4.72–5.09) Round 5 (December 30, 2022 to January 2, 2023) 47,224 4,392 2.33 (2.19–2.46) Round 6 (January 3–5, 2023) 45,968 3,593 2.61 (2.46–2.75) Round 7 (January 6–9, 2023) 50,666 2,351 1.16 (1.07–1.25) Round 8 (January 10–12, 2023) 49,206 933 0.63 (0.56–0.70) Note: North China included Hebei, Shanxi, Inner Mongolia, Liaoning, Jilin, Heilongjiang, Shandong, Henan, Shaanxi, Gansu, Qinghai, Ningxia, and Xinjiang. South China included Jiangsu, Zhejiang, Anhui, Fujian, Jiangxi, Hubei, Hunan, Guangdong, Guangxi, Hainan, Sichuan, Guizhou, Yunnan, and Xizang (Tibet).
Abbreviation: SARS-CoV-2=severe acute respiratory syndrome coronavirus 2; CI=confidence interval.Table 1. SARS-CoV-2 infection among the general population in rural China, December 2022 to January 2023.
Figure 1.Trends of SARS-CoV-2 infection among the general population in rural China, December 2022 to January 2023. (A) Trends of SARS-CoV-2 infection in total, North, and South China; (B) Trends of SARS-CoV-2 infection in eastern, central, and western China.
Note: Investigations in the study were conducted in eight rounds, from December 16, 2022 to January 12, 2023. Round 1 was conducted from December 16–19, 2022; Round 2 from December 20–22, 2022; Round 3 from December 23–26, 2022; Round 4 from December 27–29, 2022; Round 5 from December 30, 2022 to January 2, 2023; Round 6 from January 3–5, 2023; Round 7 from January 6–9, 2023; and Round 8 from January 10–12, 2023.
Abbreviation: SARS-CoV-2=severe acute respiratory syndrome coronavirus 2.
The peak of daily average newly positive rate occurred during Round 2 (December 20–22, 2022) in North China, with the highest observed in Gansu, Shandong, and Ningxia; while the peak occurred during Round 3 (December 23–26, 2022) in South China, with the highest in Hunan, Guangxi, and Zhejiang (Figure 1A). Subsequently, the daily average newly positive rate decreased by an average of 29.55% (95% CI: 15.86%–41.01%, P=0.004) per round from 5.28% in Round 2 (December 20–22, 2022) to 0.49% in Round 8 (January 10–12, 2023) in North China, which decreased more slowly than that in South China with an average decrease of 35.15% (95% CI: 23.55%–44.99%, P=0.002) per round from 5.63% in Round 3 (December 23–26, 2022) to 0.63% in Round 8 (January 10–12, 2023) (Table 1 and Figure 1A). The daily average newly positive rate converged between North and South China after Round 5 (December 30, 2022 to January 2, 2023).
Figure 1B and Table 2 illustrate the trends of SARS-CoV-2 infection in eastern, central, and western regions. The peak of daily average newly positive rate occurred during Round 2 (December 20–22, 2022) in eastern China, with the highest rates in Shandong, Zhejiang, and Hebei; while it occurred during Round 4 (December 27–29, 2022) in central China, with the highest rates in Hunan, Jiangxi, and Hubei. In eastern China, the daily average newly positive rate decreased by an average of 31.30% (95% CI: 25.15%–6.95%, P<0.001) per round from 6.09% in Round 2 (December 20–22, 2022) to 0.61% in Round 8 (January 10–12, 2023). In central China, it decreased by an average of 50.53% (95% CI: 27.54%–66.22%, P=0.010) per round from 5.99% in Round 4 (December 27–29, 2022) to 0.28% in Round 8 (January 10–12, 2023). In western China, the EDPC was -20.18% (95% CI: −32.94% to −4.99%, P=0.019) from Round 1 (December 16–19, 2022) to Round 8 (January 10–12, 2023).
Rounds Number of people investigated (n) Number of newly positive (n) Daily average newly positive rate (%, 95% CI) Eastern Round 1 (December 16–19, 2022) 11,926 1,536 3.22 (2.90–3.54) Round 2 (December 20–22, 2022) 34,638 6,333 6.09 (5.84–6.35) Round 3 (December 23–26, 2022) 62,204 12,796 5.14 (4.97–5.32) Round 4 (December 27–29, 2022) 34,451 3,766 3.64 (3.45–3.84) Round 5 (December 30, 2022 to January 2, 2023) 34,451 2,525 1.83 (1.69–1.97) Round 6 (January 3–5, 2023) 34,451 1,934 1.87 (1.73–2.01) Round 7 (January 6–9, 2023) 34,451 1,621 1.18 (1.06–1.29) Round 8 (January 10–12, 2023) 34,451 626 0.61 (0.52–0.69) Central Round 1 (December 16–19, 2022) 13,025 202 0.39 (0.28–0.49) Round 2 (December 20–22, 2022) 24,467 3,284 4.47 (4.22–4.73) Round 3 (December 23–26, 2022) 26,535 4,435 4.18 (3.94–4.42) Round 4 (December 27–29, 2022) 31,336 5,635 5.99 (5.73–6.26) Round 5 (December 30, 2022 to January 2, 2023) 31,147 3,566 2.86 (2.68–3.05) Round 6 (January 3–5, 2023) 30,791 2,224 2.41 (2.24–2.58) Round 7 (January 6–9, 2023) 31,492 1,451 1.15 (1.03–1.27) Round 8 (January 10–12, 2023) 31,499 267 0.28 (0.22–0.34) Western Round 1 (December 16–19, 2022) 15,161 2,810 4.63 (4.30–4.97) Round 2 (December 20–22, 2022) 20,919 1,878 2.99 (2.76–3.22) Round 3 (December 23–26, 2022) 24,809 4,336 4.37 (4.12–4.62) Round 4 (December 27–29, 2022) 24,681 2,636 3.56 (3.33–3.79) Round 5 (December 30, 2022 to January 2, 2023) 23,794 2,691 2.83 (2.62–3.04) Round 6 (January 3–5, 2023) 18,212 2,056 3.76 (3.49–4.04) Round 7 (January 6–9, 2023) 27,309 897 0.82 (0.71–0.93) Round 8 (January 10–12, 2023) 25,842 667 0.86 (0.75–0.97) Note: The eastern region included Hebei, Liaoning, Jiangsu, Zhejiang, Fujian, Shandong, Guangdong, and Hainan. The central region included Shanxi, Jilin, Heilongjiang, Anhui, Jiangxi, Henan, Hubei, and Hunan. The western region included Inner Mongolia, Guangxi, Sichuan, Guizhou, Yunnan, Xizang (Tibet), Shaanxi, Gansu, Qinghai, Ningxia, and Xinjiang.
Abbreviation: SARS-CoV-2=severe acute respiratory syndrome coronavirus 2; CI=confidence interval.Table 2. SARS-CoV-2 infection among the general population in rural China by region, December 2022 to January 2023.
At the provincial level, Figure 2 illustrates the daily average newly positive rate of SARS-CoV-2 infection in rural China during Round 8 (January 10–12, 2023). The highest rates were observed in Shanxi (3.21%) and Anhui (2.86%), while 15 of 27 PLADs in rural China had rates of less than 0.5%.
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