Assessing the transition of COVID-19 burden towards the young population while vaccines are rolled out in China*

References

• Global Initiative of Sharing All Influenza Data (GISAID). Tracking of hCov19 variants; 20 Mar 2022 [accessed 2022 Mar 20]. Available from: https://www.gisaid.org/hcov19-variants/
   Google Scholar
• WHO. WHO coronavirus (COVID-19) dashboard; 2021 Sep 7 [accessed 2021 Sep 7]. Available from: https://covid19.who.int/
   Google Scholar
• Yang J, Chen X, Deng X, et al. Disease burden and clinical severity of the first pandemic wave of COVID-19 in Wuhan, China. Nat Commun. 2020;11(1):5411.
   PubMed Web of Science ®Google Scholar
• Poletti P, Tirani M, Cereda D, et al. Association of age with likelihood of developing symptoms and critical disease Among close contacts exposed to patients with confirmed SARS-CoV-2 infection in Italy. JAMA Network Open. 2021;4(3):e211085.
   PubMed Web of Science ®Google Scholar
• Cerqueira-Silva T, Katikireddi SV, de Araujo Oliveira V, et al. Vaccine effectiveness of heterologous CoronaVac plus BNT162b2 in Brazil. Nat Med. 2022.
   PubMed Web of Science ®Google Scholar
• Tang P, Hasan MR, Chemaitelly H, et al. BNT162b2 and mRNA-1273 COVID-19 vaccine effectiveness against the SARS-CoV-2 Delta variant in Qatar. Nat Med. 2021.
   Web of Science ®Google Scholar
• Noh EB, Nam H-K, Lee H. Which group should be vaccinated first?: A systematic review. Infect Chemother. 2021;53(2):261–270.
   PubMed Web of Science ®Google Scholar
• CDC. Demographic characteristics of people receiving COVID-19 vaccinations in the United States; 2021 Sep 4 [accessed 2021 Sep 7]. Available from https://covid.cdc.gov/covid-data-tracker/#vaccination-demographic
   Google Scholar
• UK Health Security Agency. COVID-19 vaccine weekly surveillance reports; 2021 Nov 11 [accessed 2021 Nov 18]. Available from https://www.gov.uk/government/publications/covid-19-vaccine-weekly-surveillance-reports
   Google Scholar
• Siegel DA. Trends in COVID-19 cases, emergency department visits, and hospital admissions among children and adolescents aged 0–17 years – United States, August 2020–August 2021. MMWR Morbidity and Mortality Weekly Report. 2021; 70.
   Google Scholar
• Delahoy MJ. Hospitalizations associated with COVID-19 among children and adolescents—COVID-NET, 14 States, March 1, 2020–August 14, 2021. MMWR Morbidity and Mortality Weekly Report. 2021; 70.
   Google Scholar
• Oeser C, Whitaker H, Linley E, et al. Large increases in SARS-CoV-2 seropositivity in children in England: effects of the Delta wave and vaccination. J Infect. 2021.
   PubMed Web of Science ®Google Scholar
• Lei Z, Kai N, Hongting Z, et al. Eleven COVID-19 outbreaks with local transmissions caused by the imported SARS-CoV-2 Delta VOC – China, July–August, 2021. China CDC Weekly. 2021;3(41):863–868.
   PubMedGoogle Scholar
• News Office of Xi'an City. The 61th press conference on COVID-19 epidemic prevention and control held in Putian; 2022 Jan 20 [accessed 2022 Mar 17]. Available from: http://www.shaanxi.gov.cn/xw/sxyw/202201/t20220120_2208372.html
   Google Scholar
• Li H, Lin H, Chen X, et al. Unvaccinated children are an important link in the transmission of SARS-CoV-2 Delta variant (B1.617.2): comparative clinical evidence from a recent community surge. Front Cell Infect Microbiol. 2022;12.
   Web of Science ®Google Scholar
• The State Council Information Office PRC. Press conference held on situation regarding prevention and control of the COVID-19 epidemic and vaccination; 2021 Oct 30 [accessed 2021 Mar 19]. Available from: http://www.gov.cn/xinwen/gwylflkjz170/index.htm
   Google Scholar
• Kang M, Yi Y, Li Y, et al. Effectiveness of inactivated COVID-19 vaccines against illness caused by the B.1.617.2 (Delta) variant during an outbreak in Guangdong, China. Ann Intern Med. 2022.
   PubMed Web of Science ®Google Scholar
• Li X, Huang Y, Wang W, et al. Effectiveness of inactivated SARS-CoV-2 vaccines against the Delta variant infection in guangzhou: a test-negative case–control real-world study. Emerg Microbes Infect. 2021;10(1):1751–1759.
   PubMed Web of Science ®Google Scholar
• Hu Z, Tao B, Li Z, et al. Effectiveness of inactivated COVID-19 vaccines against severe illness in B.1.617.2 (Delta) variant–infected patients in Jiangsu, China. Int J Infect Dis. 2022;116:204–209.
   PubMed Web of Science ®Google Scholar
• Wu D, Zhang Y, Tang L, et al. Effectiveness of inactivated COVID-19 vaccines against symptomatic, pneumonia, and severe disease caused by the Delta variant: real world study and evidence – China, 2021. China CDC Weekly. 2021;4(4):57–65.
   Google Scholar
• Zhang J, Klepac P, Read JM, et al. Patterns of human social contact and contact with animals in Shanghai, China. Sci Rep. 2019;9(1):15141.
   PubMed Web of Science ®Google Scholar
• Hu S, Wang W, Wang Y, et al. Infectivity, susceptibility, and risk factors associated with SARS-CoV-2 transmission under intensive contact tracing in Hunan, China. Nat Commun. 2021;12(1):1533.
   PubMed Web of Science ®Google Scholar
• Viner RM, Mytton OT, Bonell C, et al. Susceptibility to SARS-CoV-2 infection among children and adolescents compared with adults: a systematic review and meta-analysis. JAMA Pediatr. 2021;175(2):143–156.
   PubMed Web of Science ®Google Scholar
• Li Z, Guan X, Mao N, et al. Antibody seroprevalence in the epicenter Wuhan, Hubei, and six selected provinces after containment of the first epidemic wave of COVID-19 in China. Lancet Reg Health. 2021;8:100094.
   Google Scholar
• Yang J, Marziano V, Deng X, et al. Despite vaccination, China needs non-pharmaceutical interventions to prevent widespread outbreaks of COVID-19 in 2021. Nat Hum Behav. 2021;5(8):1009–1020.
   PubMed Web of Science ®Google Scholar
• Liu H, Zhang J, Cai J, et al. Investigating vaccine-induced immunity and its effect in mitigating SARS-CoV-2 epidemics in China. BMC Med. 2022;20(1):37.
   PubMed Web of Science ®Google Scholar
• Zhang M, Xiao J, Deng A, et al. Transmission dynamics of an outbreak of the COVID-19 Delta variant B.1.617.2 – Guangdong province, China, May–June 2021. China CDC Weekly. 2021;3(27):584–586.
   PubMedGoogle Scholar
• Hart WS, Miller E, Andrews NJ, et al. Generation time of the alpha and delta SARS-CoV-2 variants: an epidemiological analysis. Lancet Infect Dis. 2022.
   PubMed Web of Science ®Google Scholar
• Pung R, Mak TM, Kucharski AJ, et al. Serial intervals in SARS-CoV-2 B.1.617.2 variant cases. Lancet. 2021.
   PubMed Web of Science ®Google Scholar
• Sun K, Wang W, Gao L, et al. Transmission heterogeneities, kinetics, and controllability of SARS-CoV-2. Science. 2020: eabe2424.
   PubMed Web of Science ®Google Scholar
• Al Kaabi N, Zhang Y, Xia S, et al. Effect of 2 inactivated SARS-CoV-2 vaccines on symptomatic COVID-19 infection in adults: A randomized clinical trial. JAMA. 2021.
   PubMed Web of Science ®Google Scholar
• Palacios R, Batista AP, Albuquerque CSN, et al. Efficacy and safety of a COVID-19 inactivated vaccine in healthcare professionals in Brazil: the PROFISCOV study. SSRN. 2021.
   Google Scholar
• Han B, Song Y, Li C, et al. Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthy children and adolescents: a double-blind, randomised, controlled, phase 1/2 clinical trial. Lancet Infect Dis. 2021.
   Web of Science ®Google Scholar
• Halloran ME, Longini IM, Struchiner CJ, Longini IM. Design and analysis of vaccine studies. Springer; 2010.
   Google Scholar
• Wang Z, Muecksch F, Schaefer-Babajew D, et al. Naturally enhanced neutralizing breadth against SARS-CoV-2 one year after infection. Nature. 2021;595(7867):426–431.
   PubMed Web of Science ®Google Scholar
• Ma Q, Liu J, Liu Q, et al. Global percentage of asymptomatic SARS-CoV-2 infections among the tested population and individuals with confirmed COVID-19 diagnosis: a systematic review and meta-analysis. JAMA Network Open. 2021;4(12):e2137257.
   PubMed Web of Science ®Google Scholar
• Nyberg T, Twohig KA, Harris RJ, et al. Risk of hospital admission for patients with SARS-CoV-2 variant B.1.1.7: cohort analysis. Br Med J. 2021;373:1412.
   PubMed Web of Science ®Google Scholar
• Piroth L, Cottenet J, Mariet A-S, et al. Comparison of the characteristics, morbidity, and mortality of COVID-19 and seasonal influenza: a nationwide, population-based retrospective cohort study. Lancet Resp Med. 2021;9(3):251–259.
   PubMed Web of Science ®Google Scholar
• Graham MS, Sudre CH, May A, et al. Changes in symptomatology, reinfection, and transmissibility associated with the SARS-CoV-2 variant B.1.1.7: an ecological study. Lancet Public Health. 2021;6(5):e335–ee45.
   PubMed Web of Science ®Google Scholar
• Sheikh A, McMenamin J, Taylor B, et al. SARS-CoV-2 Delta VOC in Scotland: demographics, risk of hospital admission, and vaccine effectiveness. Lancet. 2021.
   PubMed Web of Science ®Google Scholar
• Fisman DN, Tuite AR. Evaluation of the relative virulence of novel SARS-CoV-2 variants: a retrospective cohort study in ontario, Canada. CMAJ. 2021;193(42):E1619.
   PubMed Web of Science ®Google Scholar
• Twohig KA, Nyberg T, Zaidi A, et al. Hospital admission and emergency care attendance risk for SARS-CoV-2 delta (B.1.617.2) compared with alpha (B.1.1.7) variants of concern: a cohort study. Lancet Infect Dis. 2021.
   PubMed Web of Science ®Google Scholar
• Wang Y, Chen R, Hu F, et al. Transmission, viral kinetics and clinical characteristics of the emergent SARS-CoV-2 Delta VOC in Guangzhou, China. EClinicalMedicine. 2021;40.
   Google Scholar
• Virginia Department of Health. COVID-19 attack rates by vaccination status and age; 2021 Aug 23 [accessed 2021 Sep 7]. Available from: https://www.vdh.virginia.gov/coronavirus/2021/08/23/covid-19-attack-rates-by-vaccination-status-and-age/
   Google Scholar
• Li L, Liu Y, Wu P, et al. Influenza-associated excess respiratory mortality in China, 2010–15: a population-based study. Lancet Public Health. 2019;4(9):e473–ee81.
   PubMed Web of Science ®Google Scholar
• Zhang J, Litvinova M, Liang Y, et al. The impact of relaxing interventions on human contact patterns and SARS-CoV-2 transmission in China. Sci Adv. 2021;7(19):eabe2584.
   PubMed Web of Science ®Google Scholar
• Bosetti P, Tran Kiem C, Andronico A, et al. Epidemiology and control of SARS-CoV-2 epidemics in partially vaccinated populations: a modeling study applied to France. BMC Med. 2022;20(1):33.
   PubMed Web of Science ®Google Scholar
• Rosenberg ES, Holtgrave DR, Dorabawila V, et al. New COVID-19 cases and hospitalizations among adults, by vaccination status – New York, May 3–July 25, 2021. MMWR. 2021.
   Google Scholar
• Dyson L, Hill EM, Moore S, et al. Possible future waves of SARS-CoV-2 infection generated by variants of concern with a range of characteristics. Nat Commun. 2021;12(1):5730.
   PubMed Web of Science ®Google Scholar
• Bruxvoort KJ, Sy LS, Qian L, et al. Effectiveness of mRNA-1273 against delta, mu, and other emerging variants of SARS-CoV-2: test negative case-control study. Br Med J. 2021;375:e068848.
   PubMed Web of Science ®Google Scholar
• Walvax Biotechnology Co. A phase III clinical study of a SARS-CoV-2 messenger ribonucleic acid (mRNA) vaccine candidate against COVID-19 in population aged 18 years and above; 2021 May 17 [accessed 2021 Aug 22]. Available from: https://clinicaltrials.gov/ct2/show/NCT04847102
   Google Scholar
• Global Times. (2021). Chinese producers quickly progressing on Delta variant vaccines, ready for clinical trials; 2021 Aug 06 [accessed 2021 Aug 25]. Available from: https://www.globaltimes.cn/page/202108/1230741.shtml
   Google Scholar
• He C, Yang J, He X, et al. A bivalent recombinant vaccine targeting the S1 protein induces neutralizing antibodies against both SARS-CoV-2 variants and wild-type of the virus. MedComm. 2021;2(3):430–441.
   PubMedGoogle Scholar
• Chen Z, Zheng W, Wu Q, et al. Global diversity of policy, coverage, and demand of COVID-19 vaccines: a descriptive study. BMC Medicine. 2022;20:130.
   Google Scholar
• Abdukahil SA, Abe R, Abel L, et al. COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study. Infection. 2021;49(5):889–905.
   PubMed Web of Science ®Google Scholar
• Tsang TK, Wu P, Lin Y, et al. Effect of changing case definitions for COVID-19 on the epidemic curve and transmission parameters in mainland China: a modelling study. Lancet Public Health. 2020;5(5):e289–ee96.
   PubMed Web of Science ®Google Scholar
• The Emergency Office of Inner Mongolia. The latest situation on COVID-19 epidemic in Inner Mongolia as of March 19, 2022; 2022 Mar 20 [accessed 2022 Mar 20]. Available from http://wjw.nmg.gov.cn/ztlm/dqzt/xgfy/yqtb/202203/t20220320_2019805.html
   Google Scholar
• Nyberg T, Ferguson NM, Nash SG, et al. Comparative analysis of the risks of hospitalisation and death associated with SARS-CoV-2 omicron (B.1.1.529) and delta (B.1.617.2) variants in England: a cohort study. Lancet. 2022.
   Web of Science ®Google Scholar