Corresponding Author:
Dr Maodong Leng, Clinical Laboratory Department of Children’s Hospital
Affiliated to Zhengzhou University, No 33 of Longhu Outer Street,
Zhengzhou East District, Zhengzhou, Henan Province, China.
Tel: +8613903854186
Email: 15086632364@163.com
Conflicts of Interests
None to declare.
Running title: SARS-CoV-2 infection among children
Key words: severe acute respiratory syndrome coronavirus 2; hospitalized
children; prevention measures; nucleic acid testing.
Dear Editor
In our previous study, we demonstrated a decreased trend of influenza
infections in children1,and the infection rate of
severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) remained very low during the past three years
in China. But from December 7th of 2022, the province
and the country experienced a huge adjustment of the prevention and
control measures against SARS-CoV-2,
and we report the infection rate of SARS-CoV-2 among hospitalized
children in this study.
Since its occurrence, SARS-CoV-2
mutated from the original strain to Delta and to the present Omicron
strain, and the virulence of SARS-CoV-2 decreased markedly. But the
transmission ability of SARS-CoV-2 has been strengthened a lot, so the
difficulty in the prevention and control of infection increased
significantly. On December 7th, 2022, the country
published the ten new actions, which marked huge changes of measures
toward SARS-CoV-2. Form the ten new actions, the defined high risk area
is narrowed when infected cases appear, the society reduces nucleic acid
testing sphere of SARS-CoV-2, the check of negative nucleic acid testing
results is canceled in the majority of public places, and the infected
cases are not required to be isolated intensively.
Although the ten actions had been implemented, we still performed
regular SARS-CoV-2 nucleic acid testing for hospitalized patients before
their admission, which could to some extent reflect the infection rates
of the total society. We conducted our study from December
7th, 2022 to January 31st, 2023,
which included eight weeks. The study population included were
hospitalized children at Children’s Hospital Affiliated to Zhengzhou
University, which is a general and the largest hospital for children
with nearly two million outpatient visits and one hundred thousand
inpatients each year in central Henan, China. All the hospitalized
children would be tested of the SARS-CoV-2 infection by
nucleic acid testing before admitted
into the hospital. The oropharyngeal or nasopharyngeal swabs were used
to collect specimens from the hospitalized children, and then kept in
virus preserving fluid before transported to the laboratory for
SARS-CoV-2 nucleic acid testing. The testing was conducted by real-time
PCR method targeting the N and ORF1ab genes of SARS-CoV-2
with the Mingde detection kit (Wuhan, China) according to the
manufacturer’s instructions. Positive results were defined as the Ct
values ≤35 for both genes.
We recorded the results of each week, and the ranges of dates included
in each week were: first (December 7th to
13th, 2022), second (December 14thto 20th, 2022), third (December 21stto 27th, 2022), fourth (December
28th, 2022 to January 3rd,2023),
fifth (January 4th to 10th, 2023),
sixth (January 11th to 17th ),
seventh (January 18th to 24th,2023),
eighth (January 25th to 31st, 2023).
A total of 2212 cases and 439 positive cases were enrolled in the study.
The numbers of total cases, SARS-CoV-2 positive cases and the positive
rates of each week are shown in Table 1. The trend of SARS-CoV-2
positive rates from the first to the eighth week is demonstrated in
Figure 1. From Figure 1, it can be concluded that the infection rate
increases from the first to the third week, and then decreases from the
third to the eighth period. The infection rate of the eighth week
returned nearly to the rate of the first week. So the huge adjustment on
prevention and control measures against SARS-CoV-2 affected the spread
of infection significantly for the rapid increase of infection through
the first three weeks. The decreased trend of infection rate in the
fourth to the eighth week might be due to the fact that more and more
children had been infected and recovered from the infection.
Table 1 The numbers of total cases, SARS-CoV-2 positive cases and the
positive rates of each week