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The etiology of Rubella IgM positivity in patients with rubella‐like illness in Iran from 2011 to 2013
Author(s) -
Seyed Khorrami Seyed Mahmood,
MokhtariAzad Talat,
Yavarian Jila,
Fatemi Nasab Gazal Sadat,
Naseri Maryam,
Shafiei Jandaghi Nazanin Zahra
Publication year - 2015
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.24250
Subject(s) - rubella , rubella virus , medicine , vaccination , immunology , etiology , rash , immunoglobulin m , measles , virology , antibody , immunoglobulin g
Rubella is a mild self‐limiting contagious viral disease caused by the rubella virus (RV). Although symptoms are often mild, the concern is centralized around the possible effect on a fetus growth and development in case of primary infection during early months of pregnancy. Recently acquired rubella is commonly confirmed by RV‐specific IgM antibody detection in the serum. However, rubella primary infection is not always the only cause of IgM positivity. Other possible causes of rubella IgM positivity may include IgM persistence following vaccination or naturally acquired infection or even re‐infection. Moreover, nonspecific IgM reactivity can cause false‐positive results. There are few articles to differentiate the aetiology of rash in rubella‐like illnesses. However, limited studies have been conducted on clarifying the source of IgM positivity in these cases. This article reports the study of 10,896 clinical cases demonstrating rubella‐like illness between 2011 and 2013 in Iran. The rate of IgM positivity among these cases was 0.52% (57 cases). As predicted based on the high coverage of vaccination in Iran fewer than 16% of cases with ELISA IgM positive result, were due to current rubella primary infections. The greater part of the positive IgM reactions occurred in cross reactivity with other viruses (31.6%) or in prolonged IgM response post vaccination (24.6%). This research confirmed that the positive result of rubella IgM assay in vaccinated individuals is mainly caused by prolonged IgM production, rubella re‐infection, and false positivity due to infection with other viruses, rather than the rubella primary infection itself. J. Med. Virol. 87:1846–1852, 2015 . © 2015 Wiley Periodicals, Inc.