Association of COVID-19 Vaccination and Clinical Severity of Patients Infected with Delta or Omicron Variants — China, May 21, 2021–February 28, 2022

Abstract

What is already known about this topic?Compared with the international mRNA and adenovirus-vectored coronavirus disease 2019 (COVID-19) vaccines, there is less real-world research data about breakthrough cases in people vaccinated with China-made COVID-19 vaccines. Analyses of clinical outcomes of breakthrough cases will be an important supplement to the clinical trial efficacy and observational effectiveness data of China-made COVID-19 vaccines. What is added by this report? COVID-19 vaccine age-eligible individuals (≥3 years old) who received full primary series and a booster dose of China-made COVID-19 vaccines had good protection from pneumonia caused by Delta variant infection. There was only one serious Delta case in children (unvaccinated), but among adults 18 years and older, there was good protection from serious illness with primary vaccination and booster vaccination. Among people ≥60 years, full vaccination and booster vaccination were associated with protection from pneumonia and risk of serious COVID-19 caused by Omicron variant infection. There were few serious Omicron cases. What are the implications for public health practice? Everyone 3 years and older without contraindications should be fully vaccinated against COVID-19; schedule-eligible adults should receive booster doses. The pace of booster dose administration, especially among the elderly, should be accelerated.

Old Age is an Independent Risk Factor for Pneumonia Development in Patients with SARS-CoV-2 Omicron Variant Infection and a History of Inactivated Vaccine Injection

“…Recently, Zheng et al reported that full vaccination and a booster vaccination could protect old patients from pneumonia and serious COVID-19. 13 The kinds of vaccine, the doses of injection, and the duration between vaccination to infection may affect the protections provided by the vaccine. 10 , 17 Jassat et al reported that 37% of Omicron variant-infected patients had pneumonia in South Africa.…”

“… 3 Full vaccination and a booster vaccination can significantly protect old patients from pneumonia and serious COVID-19. 13 Considering that pneumonia is the most common manifestation of serious COVID-19, 14 analyzing the risk factors for pneumonia development in breakthrough cases with a history of inactivated vaccine injection is crucial.…”

Clinical Characteristics of COVID-19 Patients Infected by the Omicron Variant of SARS-CoV-2

“…COVID-19 patients infected by the omicron variant of SARS-CoV-2 were hospitalized and treated as reported ( 17 ). Blood cell analysis was conducted by an automated XN1000 hematology analyzer (SYSMEX, Japan), and biochemical indicators were analyzed using VITROS 350 autoanalyzer (Johnson &.…”

Vaccinate with Confidence and Finish Strong

“…In this 650,000-person outbreak, there were 588 COVID-19 deaths, and only 5% of these fatal COVID-19 cases were vaccinated. An elegant, matched case-control study by Shanghai CDC and Fudan University scientists, led by Dr. Huang and colleagues, showed that boosted primary-series vaccine effectiveness was 93% against severe COVID-19 and 96% against fatal COVID-19 -results that are nearly identical to those of McMenamin and colleagues in Hong Kong, furthering our confidence in the vaccines being used in China and emphasizing the importance of the booster dose (16).…”