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1.
Euro Surveill ; 25(23)2020 06.
Article in English | MEDLINE | ID: covidwho-2313322

ABSTRACT

We reviewed the diagnostic accuracy of SARS-CoV-2 serological tests. Random-effects models yielded a summary sensitivity of 82% for IgM, and 85% for IgG and total antibodies. For specificity, the pooled estimate were 98% for IgM and 99% for IgG and total antibodies. In populations with ≤ 5% of seroconverted individuals, unless the assays have perfect (i.e. 100%) specificity, the positive predictive value would be ≤ 88%. Serological tests should be used for prevalence surveys only in hard-hit areas.


Subject(s)
Antibodies, Viral/blood , Clinical Laboratory Techniques/methods , Coronaviridae Infections/diagnosis , Coronavirus Infections/diagnosis , Coronavirus/immunology , Pneumonia, Viral/diagnosis , Serologic Tests/standards , Severe Acute Respiratory Syndrome/immunology , Betacoronavirus , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques/standards , Coronavirus/isolation & purification , Coronavirus Infections/epidemiology , Coronavirus Infections/immunology , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/immunology , Predictive Value of Tests , SARS-CoV-2 , Sensitivity and Specificity , Serologic Tests/methods , Severe Acute Respiratory Syndrome/blood
2.
Influenza Other Respir Viruses ; 17(5): e13140, 2023 05.
Article in English | MEDLINE | ID: covidwho-2319523

ABSTRACT

Background: National Influenza Centers (NICs) have played a crucial role in the surveillance of SARS-CoV-2. The FluCov project, covering 22 countries, was initiated to monitor the impact of the SARS-CoV-2 pandemic on influenza activity. Methods: This project consisted of an epidemiological bulletin and NIC survey. The survey, designed to assess the impact of the pandemic on the influenza surveillance system, was shared with 36 NICs located across 22 countries. NICs were invited to reply between November 2021 and March 2022. Results: We received 18 responses from NICs in 14 countries. Most NICs (76%) indicated that the number of samples tested for influenza decreased. Yet, many NICs (60%) were able to increase their laboratory testing capacity and the "robustness" (e.g., number of sentinel sites) (59%) of their surveillance systems. In addition, sample sources (e.g., hospital or outpatient setting) shifted. All NICs reported a higher burden of work following the onset of the pandemic, with some NICs hiring additional staff or partial outsourcing to other institutes or departments. Many NICs anticipate the future integration of SARS-CoV-2 surveillance into the existing respiratory surveillance system. Discussion: The survey shows the profound impact of SARS-CoV-2 on national influenza surveillance in the first 27 months of the pandemic. Surveillance activities were temporarily disrupted, whilst priority was given to SARS-CoV-2. However, most NICs have shown rapid adaptive capacity underlining the importance of strong national influenza surveillance systems. These developments have the potential to benefit global respiratory surveillance in the years to come; however, questions about sustainability remain.


Subject(s)
COVID-19 , Influenza, Human , Humans , SARS-CoV-2 , Influenza, Human/epidemiology , COVID-19/epidemiology , Pandemics , Surveys and Questionnaires
3.
Euro Surveill ; 27(39)2022 09.
Article in English | MEDLINE | ID: covidwho-2054869

ABSTRACT

While two influenza B virus lineages have co-circulated, B/Yamagata-lineage circulation has not been confirmed since March 2020. The WHO FluNet database indicates that B/Yamagata-lineage detections were reported in 2021 and 2022. However, detections can result from use of quadrivalent live-attenuated vaccines. Of the type B viruses detected post-March 2020, all ascribed to a lineage have been B/Victoria-lineage. There is need for a global effort to detect and lineage-ascribe type B influenza viruses, to assess if B/Yamagata-lineage viruses have become extinct.


Subject(s)
Influenza Vaccines , Influenza, Human , Humans , Influenza B virus , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Vaccines, Attenuated , Vaccines, Combined
4.
Int J Environ Res Public Health ; 19(9)2022 04 28.
Article in English | MEDLINE | ID: covidwho-1820239

ABSTRACT

The contribution of children to viral spread in schools is still debated. We conducted a systematic review and meta-analysis of studies to investigate SARS-CoV-2 transmission in the school setting. Literature searches on 15 May 2021 yielded a total of 1088 publications, including screening, contact tracing, and seroprevalence studies. MOOSE guidelines were followed, and data were analyzed using random-effects models. From screening studies involving more than 120,000 subjects, we estimated 0.31% (95% confidence interval (CI) 0.05-0.81) SARS-CoV-2 point prevalence in schools. Contact tracing studies, involving a total of 112,622 contacts of children and adults, showed that onward viral transmission was limited (2.54%, 95% CI 0.76-5.31). Young index cases were found to be 74% significantly less likely than adults to favor viral spread (odds ratio (OR) 0.26, 95% CI 0.11-0.63) and less susceptible to infection (OR 0.60; 95% CI 0.25-1.47). Lastly, from seroprevalence studies, with a total of 17,879 subjects involved, we estimated that children were 43% significantly less likely than adults to test positive for antibodies (OR 0.57, 95% CI 0.49-0.68). These findings may not applied to the Omicron phase, we further planned a randomized controlled trial to verify these results.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , Contact Tracing , Humans , Schools , Seroepidemiologic Studies
5.
Influenza Other Respir Viruses ; 16(4): 696-706, 2022 07.
Article in English | MEDLINE | ID: covidwho-1714198

ABSTRACT

BACKGROUND: Seasonal influenza viruses undergo unpredictable changes, which may lead to antigenic mismatch between circulating and vaccine strains and to a reduced vaccine effectiveness. A continuously updated knowledge of influenza strain circulation and seasonality is essential to optimize the effectiveness of influenza vaccination campaigns. We described the global epidemiology of influenza between the 2009 A(H1N1)p and the 2020 COVID-19 pandemic. METHODS: Influenza virological surveillance data were obtained from the WHO-FluNet database. We determined the median proportion of influenza cases caused by the different influenza virus types, subtypes, and lineages; the typical timing of the epidemic peak; and the median duration of influenza epidemics (applying the annual average percentage method with a 75% threshold). RESULTS: We included over 4.6 million influenza cases from 149 countries. The median proportion of influenza cases caused by type A viruses was 75.5%, highest in the Southern hemisphere (81.6%) and lowest in the intertropical belt (73.0%), and ranged across seasons between 60.9% in 2017 and 88.7% in 2018. Epidemic peaks typically occurred during winter months in Northern and Southern hemisphere countries, while much more variability emerged in tropical countries. Influenza epidemics lasted a median of 25 weeks (range 8-42) in countries lying between 30°N and 26°S, and a median of 9 weeks (range 5-25) in countries outside this latitude range. CONCLUSIONS: This work will establish an important baseline to better understand factors that influence seasonal influenza dynamics and how COVID-19 may have affected seasonal activity and influenza virus types, subtypes, and lineages circulation patterns.


Subject(s)
COVID-19 , Influenza A Virus, H1N1 Subtype , Influenza A virus , Influenza Vaccines , Influenza, Human , COVID-19/epidemiology , Humans , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Pandemics , Seasons
8.
Int J Qual Health Care ; 33(3)2021 Sep 12.
Article in English | MEDLINE | ID: covidwho-1393278
10.
Emerg Infect Dis ; 27(5): 1537-1540, 2021 05.
Article in English | MEDLINE | ID: covidwho-1269964

ABSTRACT

Temporal variation of respiratory syncytial virus (RSV) epidemics was recently reported to be determined by the dominant RSV subtype. However, when we repeated the analysis for 4 countries in the Northern and Southern Hemispheres, the dominant subtype did not seem to affect temporal variation of RSV epidemics.


Subject(s)
Epidemics , Respiratory Syncytial Virus Infections , Respiratory Syncytial Virus, Human , DNA Viruses , Humans , Infant , Respiratory Syncytial Virus Infections/epidemiology
11.
Int J Infect Dis ; 102: 115-117, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-1060148

ABSTRACT

OBJECTIVES: Understanding the proportion of pandemic deaths captured as 'laboratory-confirmed' deaths is crucial. We assessed the ability of laboratory-confirmed deaths to capture mortality in the EU during the 2009 pandemic, and examined the likelihood that these findings are applicable to the SARS-CoV-2 pandemic. METHODS: We present unpublished results from the Global Pandemic Mortality (GLaMOR) project, in which country-specific mortality estimates were made for the 2009 influenza H1N1p pandemic. These estimates were compared with laboratory-confirmed deaths during the 2009 pandemic to estimate the ability of surveillance systems to capture pandemic mortality. RESULTS: For the 2009 influenza H1N1p pandemic, we estimated that the proportion of true pandemic deaths captured by laboratory-confirmed deaths was approximately 67%. Several differences between the two pandemics (e.g. age groups affected) make it unlikely that this capture rate will be equally high for SARS-CoV-2. CONCLUSION: The surveillance of laboratory-confirmed deaths in the EU during the 2009 pandemic was more accurate than previously assumed. We hypothesize that this method is less reliable for SARS-CoV-2. Near-real-time excess all-cause mortality estimates, routinely compiled by EuroMOMO, probably offer a better indicator of pandemic mortality. We urge more countries to join this project and that national-level absolute mortality numbers are presented.


Subject(s)
COVID-19/mortality , Influenza A Virus, H1N1 Subtype , Influenza, Human/mortality , SARS-CoV-2 , Europe/epidemiology , Humans , Time Factors
12.
Int J Environ Res Public Health ; 17(21)2020 10 27.
Article in English | MEDLINE | ID: covidwho-895364

ABSTRACT

We reviewed the association between seasonal influenza vaccination and the risk of SARS-CoV-2 infection or complicated illness or poor outcome (e.g., severe disease, need for hospitalization or ventilatory support, or death) among COVID-19 patients. None of the studies that were reviewed (n = 12) found a significant increase in the risk of infection or in the illness severity or lethality, and some reported significantly inverse associations. Our findings support measures aimed at raising influenza vaccination coverage in the coming months.


Subject(s)
Coinfection/prevention & control , Coronavirus Infections , Influenza Vaccines/administration & dosage , Influenza, Human/prevention & control , Pandemics/prevention & control , Pneumonia, Viral , Vaccination/adverse effects , Betacoronavirus , COVID-19 , Coinfection/diagnosis , Coinfection/epidemiology , Communicable Disease Control , Coronavirus Infections/diagnosis , Coronavirus Infections/mortality , Coronavirus Infections/prevention & control , Epidemics/prevention & control , Humans , Influenza Vaccines/adverse effects , Influenza, Human/diagnosis , Pneumonia, Viral/diagnosis , Pneumonia, Viral/mortality , Pneumonia, Viral/prevention & control , Risk Assessment , Risk Factors , SARS-CoV-2 , Severity of Illness Index , Vaccination/statistics & numerical data
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