Bruno Caramelli1, Maria C Escalante-Rojas1, Hiteshi K C Chauhan2, Rinaldo F Siciliano1, Marcio S Bittencourt3, Antonio C Micelli4. 1. InCor, University of São Paulo, São Paulo, Brazil. 2. Department of Cardiology, Fortis Hospital, Mohali, India. 3. Hospital Israelita Albert Einstein, Sao Paulo, Brazil; Faculdade Israelita de Ciências da Saúde Albert Einstein, São Paulo, Brazil; Center for Clinical and Epidemiological Research, University Hospital, University of Sao Paulo, Sao Paulo, Brazil. 4. Hospital das Clínicas, FMUSP, São Paulo, Brazil.
Abstract
BACKGROUND: On 12 June 2020, Brazil reached the second position worldwide in the number of COVID-19 cases. Authorities increased the number of tests performed, including the identification of antibodies to SARS-CoV-2 (IgG, IgA, and IgM). There was an overflooding of the market with several tests, and the presence of possible false-positive results became a challenge. The purpose of this study was to describe the seroprevalence and immunoglobulin blood levels in a group of asymptomatic individuals using the reference levels provided by the manufacturer. METHODS: Levels of IgG and IgA antibodies to SARS-CoV-2 were determined in blood serum by the same ELISA (enzyme-linked immunoassay) test. Patients must be free of symptoms. RESULTS: From 20 to 22 May 2020, 938 individuals were tested. There were 441 (47%) men, age 53 years (interquartile range (IQR) = 39-63.2). The sample included 335 (35.7%) subjects aged ≥60 years old. Subjects with a positive test were 54 (5.8%) for IgG and 96 (10.2%) for IgA and 42 (4.5%) for both IgG and IgA. The prevalence of IgG and IgA positive test was not different in men and women and not different in individuals under 60 and over 60 years of age. Conversely, analysing only individuals with positive tests, the levels of IgG in positive subjects were significantly higher than those with an IgA positive test, 3.00 (IQR = 1.68-5.65), and 1.95 (IQR = 1.40-3.38), respectively; P = 0.017. Additionally, individuals with isolated IgA positive tests had significantly lower levels of IgA than those with both IgA and IgG positive tests: 1.95 (IQR = 1.60-2.40) and 3.15 (IQR = 2.20-3.90), respectively, P = 0.005. These latter data suggest that IgA shows a deviation of the distribution to the left in comparison to IgG distribution data. Indeed, many subjects reported as IgA positive had immunoglobulin levels slightly elevated. CONCLUSIONS: In conclusion, we strongly suggest caution in the interpretation of IgA test results. This recommendation is more important for those with positive IgA just above the reference level.
BACKGROUND: On 12 June 2020, Brazil reached the second position worldwide in the number of COVID-19 cases. Authorities increased the number of tests performed, including the identification of antibodies to SARS-CoV-2 (IgG, IgA, and IgM). There was an overflooding of the market with several tests, and the presence of possible false-positive results became a challenge. The purpose of this study was to describe the seroprevalence and immunoglobulin blood levels in a group of asymptomatic individuals using the reference levels provided by the manufacturer. METHODS: Levels of IgG and IgA antibodies to SARS-CoV-2 were determined in blood serum by the same ELISA (enzyme-linked immunoassay) test. Patients must be free of symptoms. RESULTS: From 20 to 22 May 2020, 938 individuals were tested. There were 441 (47%) men, age 53 years (interquartile range (IQR) = 39-63.2). The sample included 335 (35.7%) subjects aged ≥60 years old. Subjects with a positive test were 54 (5.8%) for IgG and 96 (10.2%) for IgA and 42 (4.5%) for both IgG and IgA. The prevalence of IgG and IgA positive test was not different in men and women and not different in individuals under 60 and over 60 years of age. Conversely, analysing only individuals with positive tests, the levels of IgG in positive subjects were significantly higher than those with an IgA positive test, 3.00 (IQR = 1.68-5.65), and 1.95 (IQR = 1.40-3.38), respectively; P = 0.017. Additionally, individuals with isolated IgA positive tests had significantly lower levels of IgA than those with both IgA and IgG positive tests: 1.95 (IQR = 1.60-2.40) and 3.15 (IQR = 2.20-3.90), respectively, P = 0.005. These latter data suggest that IgA shows a deviation of the distribution to the left in comparison to IgG distribution data. Indeed, many subjects reported as IgA positive had immunoglobulin levels slightly elevated. CONCLUSIONS: In conclusion, we strongly suggest caution in the interpretation of IgA test results. This recommendation is more important for those with positive IgA just above the reference level.
Authors: Fiona P Havers; Carrie Reed; Travis Lim; Joel M Montgomery; John D Klena; Aron J Hall; Alicia M Fry; Deborah L Cannon; Cheng-Feng Chiang; Aridth Gibbons; Inna Krapiunaya; Maria Morales-Betoulle; Katherine Roguski; Mohammad Ata Ur Rasheed; Brandi Freeman; Sandra Lester; Lisa Mills; Darin S Carroll; S Michele Owen; Jeffrey A Johnson; Vera Semenova; Carina Blackmore; Debra Blog; Shua J Chai; Angela Dunn; Julie Hand; Seema Jain; Scott Lindquist; Ruth Lynfield; Scott Pritchard; Theresa Sokol; Lynn Sosa; George Turabelidze; Sharon M Watkins; John Wiesman; Randall W Williams; Stephanie Yendell; Jarad Schiffer; Natalie J Thornburg Journal: JAMA Intern Med Date: 2020-07-21 Impact factor: 21.873
Authors: João Roberto Cavalcante; Augusto César Cardoso-Dos-Santos; João Matheus Bremm; Andréa de Paula Lobo; Eduardo Marques Macário; Wanderson Kleber de Oliveira; Giovanny Vinícius Araújo de França Journal: Epidemiol Serv Saude Date: 2020-08-10
Authors: Jonathan J Deeks; Jacqueline Dinnes; Yemisi Takwoingi; Clare Davenport; René Spijker; Sian Taylor-Phillips; Ada Adriano; Sophie Beese; Janine Dretzke; Lavinia Ferrante di Ruffano; Isobel M Harris; Malcolm J Price; Sabine Dittrich; Devy Emperador; Lotty Hooft; Mariska Mg Leeflang; Ann Van den Bruel Journal: Cochrane Database Syst Rev Date: 2020-06-25
Authors: Marcelo Adriano da Cunha E Silva Vieira; Chrystiany Plácido de Brito Vieira; Amaríles de Souza Borba; Maria Clara de Carvalho Melo; Marilene de Sousa Oliveira; Rodrigo Moraes Melo; Vanessa Veloso Nunes; Wesllany Sousa Santana; Yara Amorim de Aguiar Journal: Rev Soc Bras Med Trop Date: 2020-07-03 Impact factor: 1.581
Authors: Sabra L Klein; Andrew Pekosz; Han-Sol Park; Rebecca L Ursin; Janna R Shapiro; Sarah E Benner; Kirsten Littlefield; Swetha Kumar; Harnish Mukesh Naik; Michael J Betenbaugh; Ruchee Shrestha; Annie A Wu; Robert M Hughes; Imani Burgess; Patricio Caturegli; Oliver Laeyendecker; Thomas C Quinn; David Sullivan; Shmuel Shoham; Andrew D Redd; Evan M Bloch; Arturo Casadevall; Aaron Ar Tobian Journal: J Clin Invest Date: 2020-11-02 Impact factor: 14.808
Authors: Carolina Lucas; Patrick Wong; Jon Klein; Tiago B R Castro; Julio Silva; Maria Sundaram; Mallory K Ellingson; Tianyang Mao; Ji Eun Oh; Benjamin Israelow; Takehiro Takahashi; Maria Tokuyama; Peiwen Lu; Arvind Venkataraman; Annsea Park; Subhasis Mohanty; Haowei Wang; Anne L Wyllie; Chantal B F Vogels; Rebecca Earnest; Sarah Lapidus; Isabel M Ott; Adam J Moore; M Catherine Muenker; John B Fournier; Melissa Campbell; Camila D Odio; Arnau Casanovas-Massana; Roy Herbst; Albert C Shaw; Ruslan Medzhitov; Wade L Schulz; Nathan D Grubaugh; Charles Dela Cruz; Shelli Farhadian; Albert I Ko; Saad B Omer; Akiko Iwasaki Journal: Nature Date: 2020-07-27 Impact factor: 49.962