Shiloh
Editor, Senior Moderator
Source: https://www.cidrap.umn.edu/news-perspective/2021/12/covid-19-scan-dec-16-2021
COVID-19 Scan for Dec 16, 2021
Vaccine-generated Omicron antibodies; Review of early CDC COVID-19 test errors
Filed Under:
COVID-19
Study finds low Omicron antibody response with COVID-19 vaccines
Only 20% and 24% of Pfizer/BioNTech COVID-19 vaccine recipients in a Chinese study had detectable neutralizing antibodies against two isolates of the highly transmissible Omicron (B.1.1.529) variant, while recipients of the Coronavac vaccine had no antibodies against either isolate.
The study, published today in Clinical Infectious Diseases after appearing on a preprint site 2 days ago, was led by University of Hong Kong researchers, who isolated Omicron strains HKU691 and HKU344-R346K from patients.
Only 20% and 24% of Pfizer vaccinees had antibodies against HKU691 and HKU344-R346K, respectively. None of the Coronavac recipients had antibodies against either strain. Among Pfizer recipients, the geometric mean antibody neutralization titers (GMT) of the Omicron isolates were 35.7- to 39.9-fold lower than those against the original 2020 strain.
The GMT of both isolates were significantly lower than those against the Beta (B1351) and Delta (B1617.2) variants, and there was no significant differences in the GMT of the Omicron variants. Coronavac is made by Beijing-based Sinovac and is the world's most-used COVID vaccine, accounting for almost half of the 8.6 billion global doses administered to date.
"Omicron variant escapes neutralizing antibodies elicited by BNT162b2 [Pfizer] or Coronavac," the authors concluded. "The additional R346K mutation did not affect the neutralization susceptibility. Our data suggest that the Omicron variant may be associated with lower COVID-19 vaccine effectiveness."
Dec 16 Clin Infect Dis study
Internal review shows first CDC COVID-19 tests inaccurate, contaminated
The first COVID-19 tests distributed by the US Centers for Disease Control and Prevention (CDC) were prone to false-positives due to flaws in assay design and contamination in assay components, according to an internal review of the tests published yesterday in PLOS One.
After the first SARS-CoV-2 genomic sequence was obtained from a patient in Wuhan, China, on Jan 12, 2020, the CDC began to develop a Real-Time RT-PCR Diagnostic Panel to identify the virus. The first tests were distributed to public health labs on Feb 5. Reports of false-positives soon followed.
The tests were composed of a diagnostic panel targeting three viral nucleocapsid gene loci (N1, N2, and N3 primers and probes), of which the N1 component was contaminated, allowing for more false-positives (2%).
CDC scientists were able to fix the N1 component, but N3 eventually had to be removed from the diagnostic panel because of a design flaw and was not included in the test that received emergency use authorization. According to a press release on the study, two molecules in the N3 probe frequently bound to each other in the absence of any virus, triggering a false positive test results.
"We conclude that flaws in both assay design and handling of the 'bulk' material caused the problems with the first lot of the 2019-nCoV Real-Time RT-PCR Diagnostic Panel," the authors wrote.
Dec 15 PLOS One study
Dec 15 PLOS press release
COVID-19 Scan for Dec 16, 2021
Vaccine-generated Omicron antibodies; Review of early CDC COVID-19 test errors
Filed Under:
COVID-19
Study finds low Omicron antibody response with COVID-19 vaccines
Only 20% and 24% of Pfizer/BioNTech COVID-19 vaccine recipients in a Chinese study had detectable neutralizing antibodies against two isolates of the highly transmissible Omicron (B.1.1.529) variant, while recipients of the Coronavac vaccine had no antibodies against either isolate.
The study, published today in Clinical Infectious Diseases after appearing on a preprint site 2 days ago, was led by University of Hong Kong researchers, who isolated Omicron strains HKU691 and HKU344-R346K from patients.
Only 20% and 24% of Pfizer vaccinees had antibodies against HKU691 and HKU344-R346K, respectively. None of the Coronavac recipients had antibodies against either strain. Among Pfizer recipients, the geometric mean antibody neutralization titers (GMT) of the Omicron isolates were 35.7- to 39.9-fold lower than those against the original 2020 strain.
The GMT of both isolates were significantly lower than those against the Beta (B1351) and Delta (B1617.2) variants, and there was no significant differences in the GMT of the Omicron variants. Coronavac is made by Beijing-based Sinovac and is the world's most-used COVID vaccine, accounting for almost half of the 8.6 billion global doses administered to date.
"Omicron variant escapes neutralizing antibodies elicited by BNT162b2 [Pfizer] or Coronavac," the authors concluded. "The additional R346K mutation did not affect the neutralization susceptibility. Our data suggest that the Omicron variant may be associated with lower COVID-19 vaccine effectiveness."
Dec 16 Clin Infect Dis study
Internal review shows first CDC COVID-19 tests inaccurate, contaminated
The first COVID-19 tests distributed by the US Centers for Disease Control and Prevention (CDC) were prone to false-positives due to flaws in assay design and contamination in assay components, according to an internal review of the tests published yesterday in PLOS One.
After the first SARS-CoV-2 genomic sequence was obtained from a patient in Wuhan, China, on Jan 12, 2020, the CDC began to develop a Real-Time RT-PCR Diagnostic Panel to identify the virus. The first tests were distributed to public health labs on Feb 5. Reports of false-positives soon followed.
The tests were composed of a diagnostic panel targeting three viral nucleocapsid gene loci (N1, N2, and N3 primers and probes), of which the N1 component was contaminated, allowing for more false-positives (2%).
CDC scientists were able to fix the N1 component, but N3 eventually had to be removed from the diagnostic panel because of a design flaw and was not included in the test that received emergency use authorization. According to a press release on the study, two molecules in the N3 probe frequently bound to each other in the absence of any virus, triggering a false positive test results.
"We conclude that flaws in both assay design and handling of the 'bulk' material caused the problems with the first lot of the 2019-nCoV Real-Time RT-PCR Diagnostic Panel," the authors wrote.
Dec 15 PLOS One study
Dec 15 PLOS press release
