Estimating global, regional, and national daily and cumulative infections with SARS-CoV-2 through Nov 14, 2021: a statistical analysis

Barber, Ryan M; Sorensen, Reed J D; Pigott, David M.; Bisignano, Catherine; Carter, Austin; Amlag, Joanne O; Collins, James K.; Abbafati, Cristiana; Adolph, Christopher; Allorant, Adrien; Aravkin, Aleksandr Y.; Bang-Jensen, Bree; Castro, Emma; Chakrabarti, Suman; Cogen, Rebecca M; Combs, Emily; Comfort, Haley; Cooperrider, Kimberly; Dai, Xiaochen; Daoud, Farah; Deen, Amanda; Earl, Lucas; Erickson, Megan; Ewald, Samuel B; Ferrari, Alize J.; Flaxman, Abraham D.; Frostad, Joseph; Fullman, Nancy; Giles, J. R.; Guo, Gaorui; He, Jiawei; Helak, Monika; Hulland, Erin N; Huntley, Bethany M; Lazzar-Atwood, Alice; LeGrand, Kate E; Lim, Stephen S; Lindstrom, Akiaja; Linebarger, Emily; Lozano, Rafael; Magistro, Beatrice; Malta, Deborah Carvalho; Månsson, Johan; Herrera, Ana Maria Mantilla; Mokdad, Ali H.; Monasta, Lorenzo; Naghavi, Mohsen; Nomura, Shuhei; Odell, Christopher M; Olana, Latera Tesfaye; Ostroff, Samuel M; Pasovic, Maja; Pease, Spencer A.; Reiner, Robert C.; Reinke, Grace; Ribeiro, Antônio Luiz Pinho; Santomauro, Damian; Sholokhov, Aleksei; Spurlock, Emma Elizabeth; Syailendrawati, Ruri; Topór-Mądry, Roman; Vo, Anh Truc; Vos, Theo; Walcott, Rebecca; Walker, Ally; Wiens, Kirsten E.; Wiysonge, Charles Shey; Worku, Nahom Alemseged; Zheng, Peng; Hay, Simon I.; Gakidou, Emmanuela; Murray, Christopher J L

doi:10.1016/s0140-6736(22)00484-6

Cited by 231 publications

(192 citation statements)

References 62 publications

(68 reference statements)

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“…Death estimates also have consequences for IFR values (the fraction of total infections in the country that leads to death) to the extent they are mainly due to SARS-CoV-2 infection. To roughly estimate the consequence on IFR values for the different excess death estimates, we used a recent paper estimating global infection until November 14, 2021, before the omicron variant (Barber et al), 12 with infection estimates partly based on e.g., seroprevalence that seem reasonable compared to the historic Nordic seroprevalence estimates, with Sweden having approximately double the infection of the other Nordic countries up to November 2021 (22.4%, vs. 7.9-13.5% Table S5 ).…”

Section: Resultsmentioning

confidence: 99%

“…However, when IHME-modelled deaths (for the shorter period, and attempted to be corrected for non-Covid-19 cases) were applied to these infection estimates, surprising IFR values resulted, with e.g., average infections in Denmark and Finland being 6-7 times more deadly than in Norway and almost doubly as deadly as in Sweden ( Table S6 ). 12 Such differences are hard to explain by population or healthcare variations, pandemic management or vaccination strategies of the Nordic countries, and warrant further scrutiny.…”

Section: Resultsmentioning

confidence: 99%

“…Another surprising consequence of this model, when combined with infection estimates, is 6-7 times higher infection fatality rates (IFR) in Finland and Denmark than in Norway, and almost double that of Sweden. 12 Due to the topic’s importance, these major differences warrant further scrutiny.…”

Section: Introductionmentioning

confidence: 99%

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Estimates of excess mortality for the five Nordic countries during the Covid-19 pandemic 2020-2021

Kepp

Björk

Kontis

et al. 2022

Preprint

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Excess mortality during the Covid-19 pandemic are of major scientific and political interest. Here we review all-cause excess mortality estimates from different methods for the five Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden), which have been much studied during the Covid-19 pandemic. In the comparison of the methods, we use simple sensitivity estimates and linear extrapolations of the death data to discuss uncertainties and implications for reporting ratios and infection fatality rates. We show using back-calculation of expected deaths from Nordic all-cause deaths that a recent study in Lancet, which is a clear outlier in the overviewed estimates, most likely substantially overestimates excess mortality of Finland and Denmark, and probably Sweden. The other estimates are more consistent and suggest a range of total Nordic excess deaths of perhaps 15−20,000, a more uniform ability to identify Covid-19-related deaths, and more similar infection fatality rates for the Nordic countries. All these estimates should be taken with caution in their interpretation as they miss detailed account of demographics, such as changes in the age group populations over the study period.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Estimates of excess mortality for the five Nordic countries during the Covid-19 pandemic 2020-2021

Kepp

Björk

Kontis

et al. 2022

Preprint

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“…Here, we first observed high prevalence (44%) of prior SARS-CoV-2 infection in Nigerian HCWs presenting for vaccination in early-2021, as determined by binding anti-N antibodies. There are no population-level SARS-CoV-2 seroprevalence data from Nigeria, but a recent modelling derived estimate of 72% in November 2021 was reported in a global analysis 22 . Anti-N Ab titres in some HCWs had declined to below cut-off in our Ab binding assay and detectable neutralisation and anti-S Ab in baseline pre-vaccine samples provided evidence of even higher prevalence of prior infection in this cohort prior to vaccination (>50%).…”

Section: Discussionmentioning

confidence: 99%

Antibody responses to AZD1222 vaccination in West Africa

Abdullahi

Oladele

Kemp

et al. 2022

Preprint

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Background: There are no data on vaccine elicited neutralising antibody responses for the most widely used vaccine, AZD1222, in African populations following scale up. Here, we measured i. baseline SARS-CoV-2 seroprevalence and levels of protective antibodies prior to vaccination rollout using both flow cytometric based analysis of binding antibodies to nucleocapsid (N), coupled with virus neutralisation approaches and ii. neutralizing antibody responses to VOC prior to vaccination (January 2021) and after two-doses of AZD1222 vaccine administered between June and July 2021 in Lagos, Nigeria, during a period when the Delta variant was also circulating. Methods: Health workers at multiple sites in Lagos were recruited to the study. For binding antibody measurement, IgG antibodies against SARS-COV-2 Wuhan-1 receptor-binding domain (RBD), trimeric spike protein (S), nucleocapsid protein (N) and Omicron S1 were measured using the Luminex-based SARS-CoV-2-IgG assay by flow cytometry. For plasma neutralising antibody measurement, SARS-CoV-2 lentiviral pseudovirus (PV) were prepared by transfecting 293T cells with Wuhan-614G wild type (WT), B.1.617.2 (Delta) and BA.1 (Omicron) plasmids in conjunction with HIV-1 expression vectors and luciferase encoding genome flanked by LTRs. We performed serial plasma dilutions from each time point and mixed plasma with PV before infecting HeLa-ACE2 cell lines, reading out luminescence and calculating ID50 (dilution of sera required to inhibit 50% of PV infection). Results: Our study population who received at least one dose of vaccine comprised 140 participants with a median age of 40 (interquartile range: 33, 48). 62/140 (44%) participants were anti-N IgG positive prior to administration of first vaccine dose. 49 had plasma samples available at baseline prior to vaccination and at two follow-up timepoints post vaccination for neutralization assays. Half of the participants, 25/49 (51%) were IgG anti-N positive at baseline. Of the 24 individuals anti-N Ab negative at baseline, 12/24 had ID50 above the cut-off of 20. In these individuals, binding antibodies to S were also detectable, and neutralisation correlated with IgG anti-S. Overall, neutralizing Ab titres to WT 1 month after second dose were 2579 and at 3 months post second-dose were 1695. As expected, lower levels of neutralization were observed against the Delta GMT 549 and Omicron variants 269 at 1 month. Positive anti-N IgG Ab status at baseline was associated with significantly higher titres of neutralizing antibodies following vaccination across all tested VOC. Those with anti-N Abs present at baseline did not experience waning of responses between months 1 and 3 post second dose. When data were analysed for negative anti-N IgG status at any timepoint, there was a significant decline in neutralization and binding antibodies between 1 month and 3 months post second-dose. The GMT in these individuals for Delta and Omicron was approximately 100, nearly a log lower in comparison to WT. We tested anti-N IgG in subjects who were anti-N IgG negative at baseline (n=78) and became positive between 1- and 3-months post second dose and found 7/49 (14%) with de-novo infection, with one additional participant demonstrating both reinfection and breakthrough infection to yield a total breakthrough rate of 8/49 (16%). Neutralising and binding Ab titres 1 month post vaccine, prior to breakthrough, did not appear to be associated with breakthrough infection. Neutralizing titres were higher at the last time point in individuals who had experienced vaccine breakthrough infection (with no evidence of infection prior to vaccine), indicating a boosting effect of infection in addition to vaccine. We noted that the increase in titres against Delta PV observed in breakthrough was significantly greater than the increase for WT and Omicron PVs, coincident with in the Delta wave of infection during the sampling period. Conclusions: AZD1222 is immunogenic in this real world west African cohort with significant background seroprevalence and incidence of breakthrough infection over a short time period. Prior infection and breakthrough infection induced higher anti-SARS-CoV-2 Ab responses at 3 months post vaccine against all widely circulating VOC. However, responses to Omicron BA.1 were reduced at three months regardless of prior exposure. Given that data suggesting that mRNA vaccine booster third doses induce broader, more potent responses with reduced mortality in the elderly, further doses after AZD1222 should be considered for those at high risk.

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“… 1 In The Lancet , Ryan Barber and colleagues, writing on behalf of the Institute for Health Metrics and Evaluation, report a comprehensive set of global and location-specific estimates of daily and cumulative SARS-CoV-2 infections and the proportion of the population infected for 190 countries and territories up to Nov 14, 2021. 2 For this, the authors used a novel approach, combining data from reported cases and deaths, excess deaths attributable to COVID-19, hospitalisations, and seroprevalence surveys to produce more robust estimates in an attempt to minimise biases. According to Barber and colleagues' findings, a staggering number of people, 3·39 billion (95% uncertainty interval 3·08–3·63) or 43·9% (39·9–46·9) of the global population, are estimated to have been infected one or more times between March, 2020, and November, 2021.…”

mentioning

confidence: 99%