Replication of SARS-CoV-2 Omicron BA.2 variant in ex vivo cultures of the human upper and lower respiratory tract

Hui, K.; Ng, Ktp; Ho, John C.W.; Yeung, Hin-Wo; Ching, Rachel H H; Gu, Hongcang; Chung, Joseph Chun Kit; Chow, Velda Ling Yu; Sit, Ko‐Yung; Hsin, Michael; Au, Wing‐Kuk; Poon, Leo L M; Peiris, Malik; Nicholls, John M.; Chan, Martin C.W.

doi:10.1016/j.ebiom.2022.104232

Cited by 74 publications

(79 citation statements)

References 25 publications

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“…Interestingly, the subsequent appearance and spread of the Omicron sublineages has then been associated with further reduction of the fatality rate, by exactly 2-fold during Omicron BA.1/2 preponderance (i.e., 0.26% versus 0.52% during the former Delta VoC wave) and by further 1.5-fold during the period of Omicron BA.4/5 surge (0.21% versus 0.26% during the former Omicron BA.1/2 wave), respectively. This epidemiological data are in keeping with the many biological studies published so far, reporting that the new Omicron sublineages are characterized by lower lethal potential on their human host, prevalently infecting the cells of the upper respiratory tract but exhibiting lower capacity to infect alveolar and inflammatory cells (25)(26)(27)(28). Overall, our epidemiological results are also aligned to those earlier published by Lauring et al in the US (29), who demonstrated that the clinical severity of COVID-19 has progressively declined over time across the country due to the combined effect of COVID-19 vaccination and virus attenuation.…”

Section: Discussionsupporting

confidence: 86%

Nationwide analysis of COVID-19 death rate throughout the pandemic in Italy

Mattiuzzi¹,

Lippi²

2022

Preprint

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Background: No definitive epidemiological evidence is available on SARS-CoV-2 lethality during the surge of different variants of concern (VoCs) and Coronavirus disease 2019 (COVID-19) vaccination in relation to Influenza virus fatality. Methods: We collected and longitudinally analyzed official data about new COVID-19 cases and COVID-9 related deaths throughout the pandemic in Italy, which were then compared with the recent flu-related fatality rate. Results: The mortality rate of COVID-19 has declined from 3.53% during predominance of the ancestral SARS-CoV-2 strain to 0.26-0.21% after surge of the new Omicron sublineages BA.1/2 and BA.4/5, when the nationwide COVID-19 vaccine coverage with primary cycle and booster doses has been concomitantly extended to 90.2% and 84.5% of the general population ≥12 years, respectively. The death rate of COVID-19 was approximately 11-fold higher than that of flu (i.e., 3.53% versus 0.32%) at the beginning of the pandemic, but has then become 36% lower after widespread COVID-19 vaccine coverage and surge of Omicron sublineages BA.4/5. Conclusions: Although our data seem to underline a reassuring epidemiological scenario, with the death rate of COVID-19 currently lower than that of influenza in Italy, we reemphasize the importance of preventing further surge of aggressiveness (and potential lethality) of SARS-CoV-2, especially in the most vulnerable parts of the population.

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Section: Discussionsupporting

confidence: 86%

Nationwide analysis of COVID-19 death rate throughout the pandemic in Italy

Mattiuzzi¹,

Lippi²

2022

Preprint

View full text Add to dashboard Cite

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“… 16 Secondly, both intramuscular CoronaVac and BNT162b2 vaccines hardly induce enough mucosal neutralizing antibody or T cell responses for prevention, 42 as Omicron replicates faster and stronger than wild type and Delta variant in the nasal and bronchial compartments but less efficiently in the lung parenchyma. 43 , 44 , 45 Critically, although CoronaVac displays lower immunogenicity than BNT162b2, it still induced memory B cell and T cell responses that can be recalled quickly for protection as demonstrated among 2 × CorV vaccinees with BNT booster and 3 × CorV vaccinees with BA.2 breakthrough infection. Therefore, recalled immune responses, especially the comparable T cell responses in different vaccinations groups, were invoked by the BA.2 breakthrough infection for protection.…”

Section: Discussionmentioning

confidence: 99%

Three-dose vaccination-induced immune responses protect against SARS-CoV-2 Omicron BA.2: a population-based study in Hong Kong

Zhou

Liu

et al. 2023

The Lancet Regional Health - Western Pacific

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“…Secondly, both CoronaVac and BNT162b2 hardly induce enough mucosal neutralizing antibody or T cell responses for prevention 43 , as Omicron replicates faster and stronger than wild type and Delta variant in the nasal and bronchial compartments but less efficiently in the lung parenchyma [44][45][46] . Critically, although CoronaVac displays lower immunogenicity than BNT162b2, it still induced memory B cell and T cell responses that can be recalled for protection as demonstrated in the 3×CorV vaccinees with BA.2 breakthrough infection.…”

Section: Discussionmentioning

confidence: 99%

Three-dose vaccination-induced immune responses protect against SARS-CoV-2 Omicron BA.2

Zhou

Liu

et al. 2022

Preprint

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SummaryThe ongoing outbreak of SARS-CoV-2 Omicron BA.2 infections in Hong Kong, the world model city of universal masking, has resulted in a major public health crisis. In this study, we investigate public servants who had been vaccinated with two dose (82.7%) or three dose (14%) of either CoronaVac (CorV) or BNT162b2 (BNT). During the BA.2 outbreak, 29.3% vaccinees were infected. Three-dose vaccination provided protection with lower incidence rates of breakthrough infections (2×BNT 49.2% vs 3×BNT 16.6%, p<0.0001; 2×CorV 48.6% vs 3×CoV 20.6%, p=0.003). The third heterologous vaccination showed the lowest incidence (2×CorV+1×BNT 6.3%). Although BA.2 conferred the highest neutralization resistance compared with variants of concern tested, the third dose vaccination-activated spike-specific memory B and Omicron cross-reactive T cell responses contributed to reduced frequencies of breakthrough infection and disease severity. Our results have implications to timely boost vaccination and immune responses likely required for vaccine-mediated protection against Omicron BA.2 pandemic.

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Replication of SARS-CoV-2 Omicron BA.2 variant in ex vivo cultures of the human upper and lower respiratory tract

Cited by 74 publications

References 25 publications

Nationwide analysis of COVID-19 death rate throughout the pandemic in Italy

Nationwide analysis of COVID-19 death rate throughout the pandemic in Italy

Three-dose vaccination-induced immune responses protect against SARS-CoV-2 Omicron BA.2: a population-based study in Hong Kong

Three-dose vaccination-induced immune responses protect against SARS-CoV-2 Omicron BA.2

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