Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 10 de 10
Filter
1.
Ann Intern Med ; 175(4): 533-540, 2022 04.
Article in English | MEDLINE | ID: covidwho-1912072

ABSTRACT

BACKGROUND: Real-world evidence on inactivated COVID-19 vaccines against the highly transmissible B.1.617.2 (Delta) variant of SARS-CoV-2 is limited, leaving an important gap in the evidence base about inactivated COVID-19 vaccines for use by immunization programs. OBJECTIVE: To estimate inactivated vaccine effectiveness (VE) against the B.1.617.2 variant. DESIGN: Retrospective cohort study. SETTING: The study was based on the first outbreak of the B.1.617.2 variant in mainland China that was discovered and traced in Guangdong in May and June 2021. PARTICIPANTS: 10 805 adult case patients with laboratory-confirmed infection and close contacts. MEASUREMENTS: Participants were categorized as unvaccinated, partially vaccinated (1 dose), and fully vaccinated (2 doses). We estimated VE against the primary outcome of pneumonia and the secondary outcomes of infections, symptomatic infections, and severe or critical illness associated with the B.1.617.2 variant. RESULTS: Results are reported in the order of outcome severity. Of 10 805 participants, 1.3% contracted infections, 1.2% developed symptomatic infections, 1.1% had pneumonia, and 0.2% had severe or critical illness. The adjusted VEs of full vaccination were 51.8% (95% CI, 20.3% to 83.2%) against infection, 60.4% (CI, 31.8% to 88.9%) against symptomatic infection, and 78.4% (CI, 56.9% to 99.9%) against pneumonia. Also, full vaccination was 100% (CI, 98.4% to 100.0%) effective against severe or critical illness. By contrast, the adjusted VEs of partial vaccination against infection, symptomatic infection, and pneumonia were 10.7% (CI, -41.2% to 62.6%), 6.8% (CI, -47.4% to 61.0%), and 11.6% (CI, -42.6% to 65.8%), respectively. LIMITATION: Observational study with possible unmeasured confounders; insufficient data to do reliable subgroup analyses by age and vaccine brand. CONCLUSION: Full vaccination with inactivated vaccines is effective against the B.1.617.2 variant. Effort should be made to ensure full vaccination of target populations. PRIMARY FUNDING SOURCE: National Natural Science Foundation of China and Key-Area Research and Development Program of Guangdong Province.


Subject(s)
COVID-19 Vaccines , COVID-19 , Adult , COVID-19/epidemiology , COVID-19/prevention & control , Cohort Studies , Critical Illness , Humans , Retrospective Studies , SARS-CoV-2/genetics , Vaccines, Inactivated
2.
China CDC Wkly ; 4(23): 494-498, 2022 Jun 10.
Article in English | MEDLINE | ID: covidwho-1893719

ABSTRACT

What is already known about this topic?: The coronavirus disease 2019 (COVID-19) pandemic has caused severe health consequences. Though most COVID-19 deaths occurred among very old people, their life-year loss might be very large because of their life expectancy at that age. What is added by this report?: This study quantified how many years of life were lost due to COVID-19 in 34 countries. COVID-19 caused 9 to 21 years of life lost (YLL) per deceased patient. East Asia and Oceania had substantially lower per capita YLL than North America and Europe. Among all countries included, the United States had the greatest total YLL, Peru had the largest YLL per 100,000 people, and Mexico had the largest YLL per 100,000 COVID-19 patients. What are the implications for public health practice?: The YLL quantification indicated that the vulnerable population, especially the elderly, should be protected under careful public health measures to reduce their YLL. It also implied that it might be too early to lift anti-epidemic restrictions now, since the extreme disproportionate consequences (total and per-capita YLL) in different countries underscored the scrutinization over the variation in disease control strategies to optimize future disease control and prevention.

3.
J Med Virol ; 94(8): 3722-3730, 2022 08.
Article in English | MEDLINE | ID: covidwho-1888725

ABSTRACT

To mitigate SARS-CoV-2 transmission, vaccines have been urgently approved. With their limited availability, it is critical to distribute the vaccines reasonably. We simulated the SARS-CoV-2 transmission for 365 days over four intervention periods: free transmission, structural mitigation, personal mitigation, and vaccination. Sensitivity analyses were performed to obtain robust results. We further evaluated two proposed vaccination allocations, including one-dose-high-coverage and two-doses-low-coverage, when the supply was low. 33.35% (infection rate, 2.68 in 10 million people) and 40.54% (2.36) of confirmed cases could be avoided as the nonpharmaceutical interventions (NPIs) adherence rate rose from 50% to 70%. As the vaccination coverage reached 60% and 80%, the total infections could be reduced by 32.72% and 41.19%, compared to the number without vaccination. When the durations of immunity were 90 and 120 days, the infection rates were 2.67 and 2.38. As the asymptomatic infection rate rose from 30% to 50%, the infection rate increased 0.92 (SD, 0.16) times. Conditioned on 70% adherence rate, with the same amount of limited available vaccines, the 20% and 40% vaccination coverage of one-dose-high-coverage, the infection rates were 2.70 and 2.35; corresponding to the two-doses-low-coverage with 10% and 20% vaccination coverage, the infection rates were 3.22 and 2.92. Our results indicated as the duration of immunity prolonged, the second wave of SARS-CoV-2 would be delayed and the scale would be declined. On average, the total infections in two-doses-low-coverage was 1.48 times (SD, 0.24) as high as that in one-dose-high-coverage. It is crucial to encourage people in order to improve vaccination coverage and establish immune barriers. Particularly when the supply is limited, a wiser strategy to prevent SARS-CoV-2 is equally distributing doses to the same number of individuals. Besides vaccination, NPIs are equally critical to the prevention of widespread of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/prevention & control , Humans , Models, Theoretical , Vaccination
4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-313731

ABSTRACT

Background: Real-world evidence (RWE) of a vaccine supplements clinical trial data by providing information in populations differing from clinical trial populations, under different epidemiological situations, on alternative outcomes, or against different pathogen lineages. To date, RWE on inactivated COVID-19 vaccines against the highly transmissible SARS-CoV-2 B.1.617.2 (Delta) variant is limited, leaving an important gap in the evidence base of inactivated COVID-19 vaccines for use by immunization programs. Methods: Between May and June 2021, an outbreak of the B.1.617.2 variant was discovered and traced in Guangdong, China. Before this outbreak, Guangdong province had started mass vaccination using inactivated vaccines approved by China’s regulator for use in adults. Using surveillance and vaccination data from the outbreak, we assessed the real-world effectiveness of inactivated vaccines against pneumonia and severe illness caused by the B.1.617.2 variant. We enrolled 10813 subjects who were close contacts of laboratory-confirmed cases, categorizing them as an unvaccinated group, a partially vaccinated (1-dose) group, and a fully vaccinated (2-dose) group. We estimated relative risk (RR) and vaccine effectiveness (VE) of the vaccinated groups in relation to the unvaccinated group. Findings: Unadjusted and adjusted VE of full vaccination against pneumonia were 77·7% (95% CI 45·1–90·9) and 69·5% (95% CI 42·8–96·3), respectively. Full vaccination was 100% effective against severe illness. Unadjusted and adjusted VE of partial vaccination against pneumonia were 1·4% (95% CI -79·7–45·9) and 8·4% (95% CI -47·6–64·4). Interpretation Full vaccination with inactivated vaccines is effective against pneumonia, severe, and critical illness caused by the B.1.617.2 variant. Effort should be placed to ensure full vaccination of target populations. Funding: National Natural Science Foundation of China and Key-Area Research and Development Program of Guangdong.Declaration of Interest: None to declare. Ethical Approval: This study was approved by the institutional ethics committee of the Guangdong Provincial Center for Disease Control and Prevention (GDCDC). Data in the study were collected per administrative requirements of disease control and surveillance, and were anonymized for analysis. Participants were informed about the requirements of disease surveillance and provided oral consents.

5.
Hum Vaccin Immunother ; 17(12): 4971-4981, 2021 12 02.
Article in English | MEDLINE | ID: covidwho-1565874

ABSTRACT

BACKGROUND: Men who have sex with men (MSM), a population bearing the greatest HIV burden in many countries, may also be vulnerable to COVID-19. COVID-19 vaccines are essential to containing the pandemic. However, vaccine hesitancy may compromise vaccine coverage. We aimed to understand the uptake of COVID-19 vaccine and factors associated with COVID-19 vaccine hesitancy among HIV-infected MSM in mainland China. METHODS: A cross-sectional online survey among HIV-infected MSM was conducted between 13 and 21 February 2021 in mainland China. Variables including demographics, mental health status, HIV characteristics, and knowledge of and attitudes toward COVID-19 pandemic and COVID-19 vaccine were collected. Chi-square tests and multivariable logistic regression were used to analyze factors associated with COVID-19 vaccine hesitancy. RESULTS: A total of 1295 participants were included. The median age was 29.3 years (interquartile range [IQR] 25.2-34.0 years). The uptake of COVID-19 vaccine was 8.7%. Two main reasons for receiving vaccines were "regarded vaccination as self-health protection" (67.3%) and "trust in domestic medical technology" (67.3%). Among participants who did not initiate vaccination, concern about side effects (46.4%) and disclosure of HIV infection (38.6%) were top two reasons, and 47.2% had higher vaccine hesitancy. Men who had with high antiretroviral therapy (ART) adherence (adjusted odds ratio [aOR] 0.53, 95% confidence interval [CI] 0.35-0.80), often (0.26, 0.17-0.40) or sometimes (0.46, 0.31-0.67) paid attention to information about the COVID-19 vaccine, preferred domestic vaccines (0.37, 0.24-0.59), thought the pandemic had moderate (0.58, 0.38-0.90) and moderately severe or severe impact (0.54, 0.38-0.78) on immunity, who were waiting for vaccination programs organized at workplace (0.60, 0.44-0.81) and who were unaware of where to get COVID-19 vaccine (0.61, 0.45-0.82) had lower degree of COVID-19 vaccine hesitancy. Men who were concerned about the efficacy (1.72, 1.16-2.54) and side effects (2.44, 1.78-3.35) had higher degree of COVID-19 vaccine hesitancy. CONCLUSION: COVID-19 vaccine uptake among HIV-infected MSM is still suboptimal. Understanding influencing factors of vaccine hesitancy among this group and making tailored measures to alleviate hesitancy would help improve the coverage of COVID-19 vaccination in this population.


Subject(s)
COVID-19 , HIV Infections , Sexual and Gender Minorities , Adult , COVID-19/prevention & control , COVID-19 Vaccines , China/epidemiology , Cross-Sectional Studies , HIV Infections/complications , HIV Infections/epidemiology , Homosexuality, Male , Humans , Male , Pandemics , SARS-CoV-2 , Vaccination
6.
Infect Dis Model ; 7(1): 109-121, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1561116

ABSTRACT

OBJECTIVE: The present study aimed to document the economic profiles of inactivated COVID-19 vaccines in Hong Kong SAR, Indonesia, mainland China, Philippines, Singapore, and Thailand, the evidence on which is currently absent. METHODS: Decision tree models were developed to assess the cost-effectiveness of two doses of inactivated COVID-19 vaccines at a population vaccination rate of 50% in the base case, which was an estimate of feasible vaccination coverage according to previous studies. Epidemiological, mortality, cost, and health state utility information were sourced from the literature. Vaccine efficacy against COVID-19 cases by severity were estimated using meta-analyses of publicly accessible phase 3 trial results of inactivated vaccines. The health outcomes were quantified as quality-adjusted life years (QALYs) and compared across the vaccination and no vaccination strategies. In scenario analyses, incidence and vaccination rates were changed semi-continuously over spectrums, the results of which were presented as contour lines informing the efficiency frontiers of vaccination strategies. One-way and probabilistic sensitivity analyses were also conducted. RESULTS: The vaccination strategy was dominant in all jurisdictions in the base case by producing 105.18, 98.15, 99.70, 60.48, 112.00, and 103.47 QALYs while saving US$40.26 million, US$5.26 million, US$7.60 million, US$5.91 million, US$21.33 million, and US$7.18 million in Hong Kong SAR, Indonesia, mainland China, Philippines, Singapore, and Thailand per every 100,000 vaccinated individuals, respectively. Results were robust in alternative model specifications. CONCLUSIONS: Inactivated COVID-19 vaccines may be cost-saving options in Hong Kong SAR, Indonesia, mainland China, Philippines, Singapore, and Thailand. Mass vaccination programs using inactivated COVID-19 vaccines should be considered in these jurisdictions.

7.
J Med Virol ; 93(2): 1171-1174, 2021 02.
Article in English | MEDLINE | ID: covidwho-1196457

ABSTRACT

Several randomized clinical trials (RCTs) that investigated the effectiveness of remdesivir for the treatment of coronavirus disease-2019 (COVID-19) have generated inconsistent evidence. The present study aimed to synthesize available RCT evidence using network meta-analyses (NMAs). Both blinded and open-label RCTs in PubMed database from inception to 7 June 2020 that contained "remdesivir", "Covid-19", and "trial" in the abstracts conducted on hospitalized COVID-19 persons were identified and screened. The studies must have at least one remdesivir arm and evaluated one of the pre-specified outcomes. The outcomes were clinical improvement between days 10 to 15 after randomization and clinical recovery during the follow-up period. The identified literature was supplemented with relatively recent studies that were known to the researchers if not already included. Frequentist NMAs with random effects were conducted. Both 10-day and 5-day remdesivir regimens were associated with higher odds of clinical improvement (odds ratio [OR] of 10-day regimen: 1.35, 95% confidence interval [CI], 1.09-1.67); OR of 5-day regimen: 1.81, 95% CI, 1.32-2.45, and higher probabilities of clinical recovery (relative risk [RR] of 10-day regimen: 1.24, 95% CI, 1.07-1.43; RR of 5-day regimen: 1.47, 95% CI, 1.16-1.87 compared with placebo. Remdesivir may have clinical benefits among hospitalized COVID-19 persons.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Network Meta-Analysis , Adenosine Monophosphate/therapeutic use , Alanine/therapeutic use , Hospitalization/statistics & numerical data , Humans , Treatment Outcome
8.
Br J Clin Pharmacol ; 87(11): 4386-4396, 2021 11.
Article in English | MEDLINE | ID: covidwho-1186137

ABSTRACT

AIMS: The present study aimed to evaluate the cost-effectiveness of the 5-day remdesivir regimen compared with standard of care among severe COVID-19 patients in China, the evidence on which is essential to inform the necessity of securing access to remdesivir. METHODS: A dynamic transmission model that extended the susceptible-exposed-infected-recovered framework by incorporating asymptomatic, presymptomatic and waiting-to-be-diagnosed patients was constructed to conduct the cost-effectiveness analysis from the healthcare system perspective. To estimate epidemic parameters, the model was first calibrated to the observed epidemic curve in Wuhan from 23 January to 19 March 2020. Following the calibration, the infected compartment was replaced by 3 severity-defined health states to reflect differential costs and quality of life associated with disease gravity. Costs and quality-adjusted life year (QALY) outcomes of 9 million simulated people were accrued across time to evaluate the incremental cost-effectiveness ratio of remdesivir. As robustness checks, an alternative modelling technique using decision tree, additional epidemic scenarios representing different epidemic intensities, and 1-way parameter variations were also analysed. RESULTS: Remdesivir treatment cost CN¥97.93 million more than standard of care. Also, the net QALY gain from 5-day remdesivir treatment was 6947 QALYs. As such, the incremental cost-effectiveness ratio was CN¥14 098/QALY, substantially lower than the gross domestic product per capita threshold. The peak daily number of severe cases was 19% lower in the remdesivir treatment strategy. Overall, results were robust in alternative scenarios and sensitivity analyses. CONCLUSION: Given the cost-effectiveness profile, access to remdesivir for severe COVID-19 patients in China should be considered.


Subject(s)
Adenosine Monophosphate , Alanine , Antiviral Agents/therapeutic use , COVID-19 , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/economics , Adenosine Monophosphate/therapeutic use , Alanine/analogs & derivatives , Alanine/economics , Alanine/therapeutic use , Antiviral Agents/economics , COVID-19/drug therapy , COVID-19/economics , China , Cost-Benefit Analysis , Humans , Quality of Life
9.
J Med Internet Res ; 22(11): e23853, 2020 11 11.
Article in English | MEDLINE | ID: covidwho-976121

ABSTRACT

BACKGROUND: The novel COVID-19 disease has spread worldwide, resulting in a new pandemic. The Chinese government implemented strong intervention measures in the early stage of the epidemic, including strict travel bans and social distancing policies. Prioritizing the analysis of different contributing factors to outbreak outcomes is important for the precise prevention and control of infectious diseases. We proposed a novel framework for resolving this issue and applied it to data from China. OBJECTIVE: This study aimed to systematically identify national-level and city-level contributing factors to the control of COVID-19 in China. METHODS: Daily COVID-19 case data and related multidimensional data, including travel-related, medical, socioeconomic, environmental, and influenza-like illness factors, from 343 cities in China were collected. A correlation analysis and interpretable machine learning algorithm were used to evaluate the quantitative contribution of factors to new cases and COVID-19 growth rates during the epidemic period (ie, January 17 to February 29, 2020). RESULTS: Many factors correlated with the spread of COVID-19 in China. Travel-related population movement was the main contributing factor for new cases and COVID-19 growth rates in China, and its contributions were as high as 77% and 41%, respectively. There was a clear lag effect for travel-related factors (previous vs current week: new cases, 45% vs 32%; COVID-19 growth rates, 21% vs 20%). Travel from non-Wuhan regions was the single factor with the most significant impact on COVID-19 growth rates (contribution: new cases, 12%; COVID-19 growth rate, 26%), and its contribution could not be ignored. City flow, a measure of outbreak control strength, contributed 16% and 7% to new cases and COVID-19 growth rates, respectively. Socioeconomic factors also played important roles in COVID-19 growth rates in China (contribution, 28%). Other factors, including medical, environmental, and influenza-like illness factors, also contributed to new cases and COVID-19 growth rates in China. Based on our analysis of individual cities, compared to Beijing, population flow from Wuhan and internal flow within Wenzhou were driving factors for increasing the number of new cases in Wenzhou. For Chongqing, the main contributing factor for new cases was population flow from Hubei, beyond Wuhan. The high COVID-19 growth rates in Wenzhou were driven by population-related factors. CONCLUSIONS: Many factors contributed to the COVID-19 outbreak outcomes in China. The differential effects of various factors, including specific city-level factors, emphasize the importance of precise, targeted strategies for controlling the COVID-19 outbreak and future infectious disease outbreaks.


Subject(s)
COVID-19/epidemiology , Disease Outbreaks/statistics & numerical data , China/epidemiology , Factor Analysis, Statistical , Humans
10.
BMJ Glob Health ; 5(7)2020 07.
Article in English | MEDLINE | ID: covidwho-659487

ABSTRACT

OBJECTIVES: The objectives were to evaluate the effectiveness of conducting three versus two reverse transcription-PCR (RT-PCR) tests for diagnosing and discharging people with COVID-19 with regard to public health and clinical impacts by incorporating asymptomatic and presymptomatic infection and to compare the medical costs associated with the two strategies. METHODS: A model that consisted of six compartments was built. The compartments were the susceptible (S), the asymptomatic infective (A), the presymptomatic infective (L), the symptomatic infective (I), the recovered (R), and the deceased (D). The A, L and I classes were infective states. To construct the model, several parameters were set as fixed using existing evidence and the rest of the parameters were estimated by fitting the model to a smoothed curve of the cumulative confirmed cases in Wuhan from 24 January 2020 to 6 March 2020. Input data about the cost-effectiveness analysis were retrieved from the literature. RESULTS: Conducting RT-PCR tests three times for diagnosing and discharging people with COVID-19 reduced the estimated total number of symptomatic cases to 45| 013 from 51 144 in the two-test strategy over 43 days. The former strategy also led to 850.1 quality-adjusted life years (QALYs) of health gain and a net healthcare expenditure saving of CN¥49.1 million. About 100.7 QALYs of the health gain were attributable to quality-adjusted life day difference between the strategies during the analytic period and 749.4 QALYs were attributable to years of life saved. CONCLUSIONS: More accurate strategies and methods of testing for the control of COVID-19 may reduce both the number of infections and the total medical costs. Increasing the number of tests should be considered in regions with relatively severe epidemics when existing tests have moderate sensitivity.


Subject(s)
Coronavirus Infections/diagnosis , Cost-Benefit Analysis , Patient Discharge/statistics & numerical data , Pneumonia, Viral/diagnosis , Reverse Transcriptase Polymerase Chain Reaction/economics , Reverse Transcriptase Polymerase Chain Reaction/methods , Asymptomatic Diseases/epidemiology , Betacoronavirus , COVID-19 , China/epidemiology , Coronavirus Infections/epidemiology , Humans , Pandemics , Pneumonia, Viral/epidemiology , SARS-CoV-2
SELECTION OF CITATIONS
SEARCH DETAIL