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1.
Stat Med ; 42(12): 1869-1887, 2023 05 30.
Article in English | MEDLINE | ID: covidwho-20236518

ABSTRACT

The ICH E9 (R1) addendum proposes five strategies to define estimands by addressing intercurrent events. However, mathematical forms of these targeted quantities are lacking, which might lead to discordance between statisticians who estimate these quantities and clinicians, drug sponsors, and regulators who interpret them. To improve the concordance, we provide a unified four-step procedure for constructing the mathematical estimands. We apply the procedure for each strategy to derive the mathematical estimands and compare the five strategies in practical interpretations, data collection, and analytical methods. Finally, we show that the procedure can help ease tasks of defining estimands in settings with multiple types of intercurrent events using two real clinical trials.


Subject(s)
Models, Statistical , Research Design , Humans , Data Interpretation, Statistical , Data Collection
2.
Engineering (Beijing) ; 2022 Feb 02.
Article in English | MEDLINE | ID: covidwho-2262070

ABSTRACT

Seasonal influenza activity typically peaks in the winter months but plummeted globally during the current coronavirus disease 2019 (COVID-19) pandemic. Unraveling lessons from influenza's unprecedented low profile is critical in informing preparedness for incoming influenza seasons. Here, we explored a country-specific inference model to estimate the effects of mask-wearing, mobility changes (international and domestic), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) interference in China, England, and the United States. We found that a one-week increase in mask-wearing intervention had a percent reduction of 11.3%-35.2% in influenza activity in these areas. The one-week mobility mitigation had smaller effects for the international (1.7%-6.5%) and the domestic community (1.6% to 2.8%). In 2020-2021, the mask-wearing intervention alone could decline percent positivity by 13.3-19.8. The mobility change alone could reduce percent positivity by 5.2-14.0, of which 79.8%-98.2% were attributed to the deflected international travel. Only in 2019-2020, SARS-CoV-2 interference had statistically significant effects. There was a reduction in percent positivity of 7.6 (2.4-14.4) and 10.2 (7.2-13.6) in northern China and England, respectively. Our results have implications for understanding how influenza evolves under non-pharmaceutical interventions and other respiratory diseases and will inform health policy and the design of tailored public health measures.

4.
China CDC Wkly ; 4(31): 673-679, 2022 Aug 05.
Article in English | MEDLINE | ID: covidwho-1989059

ABSTRACT

What is already known about this topic?: Government used mobility restrictions to help contain the first wave of coronavirus disease 2019 (COVID-19) across cities in China. The restrictions were lifted during times of non-zero incidence in response to a return to work order that went into effect on February 10, 2020. What is added by this report?: The effect of lifting mobility restrictions on COVID-19 death rate and incidence varied by city, with smaller increases or even reductions in cities with low community connectivity and small floating volume, and larger increases in cities with high community connectivity and large floating volume. Effects on recovery rates were similar across cities. What are the implications for public health practice?: City-specific mobility restriction lifting is likely to be beneficial. Two indexes, community connectivity and floating volume, can inform the design of city-specific mobility restriction lifting policies.

5.
Vaccine ; 40(36): 5322-5332, 2022 08 26.
Article in English | MEDLINE | ID: covidwho-1967205

ABSTRACT

BACKGROUND: The safety and immunogenicity of the coadministration of an inactivated SARS-CoV-2 vaccine (Sinopharm BBIBP-CorV), quadrivalent split-virion inactivated influenza vaccine (IIV4), and 23-valent pneumococcal polysaccharide vaccine (PPV23) in adults in China is unknown. METHODS: In this open-label, non-inferiority, randomised controlled trial, participants aged ≥ 18 years were recruited from the community. Individuals were eligible if they had no history of SARS-CoV-2 vaccine or any pneumonia vaccine and had not received an influenza vaccine during the 2020-21 influenza season. Eligible participants were randomly assigned (1:1:1), using block randomization stratified, to either: SARS-CoV-2 vaccine and IIV4 followed by SARS-CoV-2 vaccine and PPV23 (SARS-CoV-2 + IIV4/PPV23 group); two doses of SARS-CoV-2 vaccine (SARS-CoV-2 vaccine group); or IIV4 followed by PPV23 (IIV4/PPV23 group). Vaccines were administered 28 days apart, with blood samples taken on day 0 and day 28 before vaccination, and on day 56. RESULTS: Between March 10 and March 15, 2021, 1152 participants were recruited and randomly assigned to three groups (384 per group). 1132 participants were included in the per-protocol population (375 in the SARS-CoV-2 + IIV4/PPV23 group, 380 in the SARS-CoV-2 vaccine group, and 377 in the IIV4/PPV23 group). The seroconversion rate (100 % vs 100 %) and GMT (159.13 vs 173.20; GMT ratio of 0.92 [95 % CI 0.83 to 1.02]) of SARS-CoV-2 neutralising antibodies in the SARS-CoV-2 + IIV4/PPV23 group was not inferior to those in the SARS-CoV-2 vaccine group. The SARS-CoV-2 + IIV4/PPV23 group was not inferior to the IIV4/PPV23 group in terms of seroconversion rates and GMT of influenza virus antibodies for all strains except for the seroconversion rate for the B/Yamagata strain. The SARS-CoV-2 + IIV4/PPV23 group was not inferior to the IIV4/PPV23 group regarding seroconversion rates and GMC of Streptococcus pneumoniae IgG antibodies specific to all serotypes. All vaccines were well tolerated. CONCLUSIONS: The coadministration of the inactivated SARS-CoV-2 vaccine and IIV4/PPV23 is safe with satisfactory immunogenicity. This study is registered with ClinicalTrials.gov, NCT04790851.


Subject(s)
COVID-19 Vaccines , COVID-19 , Immunogenicity, Vaccine , Influenza Vaccines , Influenza, Human , Pneumococcal Infections , Pneumococcal Vaccines , Adult , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , China , Double-Blind Method , Hemagglutination Inhibition Tests/methods , Humans , Influenza B virus , Influenza, Human/prevention & control , Pneumococcal Infections/prevention & control , Pneumococcal Vaccines/adverse effects , SARS-CoV-2 , Vaccines, Combined , Vaccines, Inactivated , Virion
6.
China CDC Wkly ; 3(49): 1039-1045, 2021 Dec 03.
Article in English | MEDLINE | ID: covidwho-1579156

ABSTRACT

INTRODUCTION: Seasonal influenza activity has declined globally since the widespread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. There has been scarce information to understand the future dynamics of influenza - and under different hypothesis on relaxation of non-pharmaceutical interventions (NPIs) in particular - after the disruptions to seasonal patterns. METHODS: We collected data from public sources in China, the United Kingdom, and the United States, and forecasted the influenza dynamics in the incoming 2021-2022 season under different NPIs. We considered Northern China and Southern China separately, due to the sharp difference in the patterns of seasonal influenza. For the United Kingdom, data were collected for England only. RESULTS: Compared to the epidemics in 2017-2019, longer and blunter influenza outbreaks could occur should NPIs be fully lifted, with percent positivity varying from 10.5 to 18.6 in the studying regions. The rebounds would be smaller if the mask-wearing intervention continued or the international mobility stayed low, but sharper if the mask-wearing intervention was lifted in the middle of influenza season. Further, influenza activity could stay low under a much less stringent mask-wearing intervention coordinated with influenza vaccination. CONCLUSIONS: The results added to our understandings of future influenza dynamics after the global decline during the coronavirus disease 2019 (COVID-19) pandemic. In light of the uncertainty on the incoming circulation strains and the relatively low negative impacts of mask wearing on society, our findings suggested that wearing mask could be considered as an accompanying mitigation measure in influenza prevention and control, especially for seasons after long periods of low-exposure to influenza viruses.

7.
Nat Commun ; 12(1): 4673, 2021 08 03.
Article in English | MEDLINE | ID: covidwho-1340997

ABSTRACT

Dynamically adapting the allocation of COVID-19 vaccines to the evolving epidemiological situation could be key to reduce COVID-19 burden. Here we developed a data-driven mechanistic model of SARS-CoV-2 transmission to explore optimal vaccine prioritization strategies in China. We found that a time-varying vaccination program (i.e., allocating vaccines to different target groups as the epidemic evolves) can be highly beneficial as it is capable of simultaneously achieving different objectives (e.g., minimizing the number of deaths and of infections). Our findings suggest that boosting the vaccination capacity up to 2.5 million first doses per day (0.17% rollout speed) or higher could greatly reduce COVID-19 burden, should a new wave start to unfold in China with reproduction number ≤1.5. The highest priority categories are consistent under a broad range of assumptions. Finally, a high vaccination capacity in the early phase of the vaccination campaign is key to achieve large gains of strategic prioritizations.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Health Care Rationing/methods , Mass Vaccination/methods , Basic Reproduction Number , COVID-19/epidemiology , COVID-19/transmission , China/epidemiology , Health Priorities , Humans , Incidence , Models, Theoretical , SARS-CoV-2/immunology , Vaccination Coverage
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