No neutralizing effect of pre-existing tick-borne encephalitis virus antibodies against severe acute respiratory syndrome coronavirus-2: a prospective healthcare worker study

• Published in: Scientific reports Vol. 11; no. 1; p. 24198
• Main Authors: Kohler, Philipp, Jonsdottir, Hulda R., Risch, Lorenz, Vernazza, Pietro, Ackermann-Gäumann, Rahel, Kahlert, Christian R.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17-12-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 631/250/2152/2153/1291; 631/250/255/2514; Adult; Antibodies; Antibodies, Neutralizing - immunology; Antibodies, Viral - immunology; Coronaviruses; COVID-19; COVID-19 - epidemiology; COVID-19 - immunology; COVID-19 - virology; Cross Protection - immunology; Cross-protection; Encephalitis; Encephalitis Viruses, Tick-Borne - immunology; Encephalitis Viruses, Tick-Borne - physiology; Encephalitis, Tick-Borne - immunology; Encephalitis, Tick-Borne - virology; Female; Health care; Health Personnel - statistics & numerical data; Humanities and Social Sciences; Humans; Immune response; Immunoglobulin G; Immunoglobulin G - immunology; Laboratory tests; Male; Medical personnel; Middle Aged; multidisciplinary; Neutralization; Pandemics - prevention & control; Prospective Studies; SARS-CoV-2 - immunology; SARS-CoV-2 - physiology; Science; Science (multidisciplinary); Seroconversion; Severe acute respiratory syndrome coronavirus 2; Tick-borne encephalitis; Vaccination; Viruses
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-03685-y

Certain immunizations including vaccination against tick-borne encephalitis virus (TBEV) have been suggested to confer cross-protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Within a prospective healthcare worker (HCW) cohort, we assessed the potentially protective role of anti-TBEV antibodies against SARS-CoV-2 infection. Among 3352 HCW, those with ≥ 1 previous TBEV vaccination (n = 2018, 60%) showed a reduced risk of SARS-CoV-2 seroconversion (adjusted odds ratio: 0.8, 95% CI: 0.7–1.0, P = 0.02). However, laboratory testing of a subgroup of 26 baseline and follow-up samples did not demonstrate any neutralizing effect of anti-TBEV antibodies against SARS-CoV-2 in live-virus neutralization assay. However, we observed significantly higher anti-TBEV antibody titers in follow-up samples of participants with previous TBEV vaccination compared to baseline, both TBEV neutralizing (p = 0.001) and total IgG (P < 0.0001), irrespective of SARS-CoV-2 serostatus. Based on these data, we conclude that the observed association of previous TBEV vaccination and reduced risk of SARS-CoV-2 infection is likely due to residual confounding factors. The increase in TBEV follow-up antibody titers can be explained by natural TBEV exposure or potential non-specific immune activation upon exposure to various pathogens, including SARS-CoV-2. We believe that these findings, although negative, contribute to the current knowledge on potential cross-immunity against SARS-CoV-2 from previous immunizations.