Genomic Surveillance for SARS-CoV-2—China,September 26,2022 to January 29,2023

Introduction:The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has generated 2,431 variants over the course of its global transmission over the past 3 years.To better evaluate the genomic variation of SARS-CoV-2 before and after the optimization of coronavirus disease 2019(COVID-19)prevention and control strategies,we analyzed the genetic evolution branch composition and genomic variation of SARS-CoV-2 in both domestic and imported cases in China(the data from Hong Kong and Macao Special Administrative Regions and Taiwan,China were not included)from September 26,2022 to January 29,2023.Methods:Analysis of the number of genome sequences,sampling time,dynamic changes of evolutionary branches,origin,and clinical typing of SARS-CoV-2 variants submitted by 31 provincial-level administrative divisions(PLADs)and Xinjiang Production and Construction Corps(XPCC)was conducted to assess the accuracy and timeliness of SARS-CoV-2 variant surveillance.Results:From September 26,2022 to January 29,2023,20,013 valid genome sequences of domestic cases were reported in China,with 72 evolutionary branches.Additionally,1,978 valid genome sequences of imported cases were reported,with 169 evolutionary branches.The prevalence of the Omicron variants of SARS-CoV-2 in both domestic and imported cases was consistent with that of international epidemic variants.Conclusions:This study provides an overview of the prevalence of Omicron variants of SARS-CoV-2 in China.After optimizing COVID-19 prevention and control strategies,no novel Omicron variants of SARSCoV-2 with altered biological characteristics or public health significance have been identified since December 1,2022.

Serological Investigation of Laboratory-Confirmed and Suspected Ebola Virus Disease Patients During the Late Phase of the Ebola Outbreak in Sierra Leone

This study aimed to investigate the serological characteristics of Ebola virus(EBOV) infection during the late phase of the Ebola outbreak in Sierra Leone. In total, 877 blood samples from 694 suspected Ebola virus disease(EVD) cases assessed from March to December 2015, were analyzed via real-time reverse transcription polymerase chain reaction(RT-PCR) for viral RNA and enzyme-linked immunosorbent assay(ELISA) and Luminex to detect antibodies against EBOV. Viral load and EBOV-specific IgM/IgG titers displayed a declining trend during March to December 2015. Viral RNA load decreased rapidly at earlier stages after disease onset, while EBOV-specific IgM and IgG still persisted in 58.1%(18/31) and 93.5%(29/31) of the confirmed EVD patients and in 3.8%(25/663) and 17.8%(118/663) of the RNA-negative suspected patients in the later phase, respectively. Dynamic analysis of longitudinally collected samples from eight EVD patients revealed typically reversed trends of declining viral load and increasing IgM and/or IgG titers in response to the EBOV infection.The present results indicate that certain populations of Sierra Leone developed immunity to an EBOV infection in the late phase of the outbreak, providing novel insights into the risk assessment of EBOV infections among human populations.