02652nas a2200229 4500008004100000024000700041245011200048210006900160260001500229300001200244490000700256520196500263653001202228653001202240653002602252100001902278700003802297700002302335700000502358700001902363856004002382 2023 eng d a2500aAnalysis of Covid-19 Neutralizing Antibody Levels Post Vaccination using Ichroma™ and iFlash Covid-19 Nab0 aAnalysis of Covid19 Neutralizing Antibody Levels Post Vaccinatio cMarch 2023 a171-1740 v153 a

Background: One of the efforts to control SARS-CoV-2 infection in health workers is vaccination. In this study, the levels of SARS-CoV-2 neutralizing antibody (nAb) in health workers were measured with Ichroma and iFlash. Methods: This study applied an observational analytic design with a prospective cohort and was conducted at Dr. Soetomo Regional Public Hospital, Surabaya, from January to November 2021. The population of this study included a total of 75 health workers after taking the second dose of the SARS-CoV-2 (Sinovac) vaccine. The Covid-19 NAb levels of the population were tested with Ichroma and iFlash on day 0 before vaccination, as well as days 14 and 28, and months 3 and 6 after vaccination. Results: The Friedman test indicated a significant difference in NAb levels according to the iFlash test on day 14, day 28, month 3, and month 6 compared to those before vaccination (p < 0.05). The Wilcoxon test revealed a significant difference in NAb levels on day 14, day 28, month 3, and month 6. The results of the Cochran test showed a significant difference in the positivity of NAb according to the Ichroma test on day 14, day 28, month 3, and month 6 compared to those before vaccination (p < 0.05). McNemar's test demonstrated that the COI at month 3 was not significantly different from that before vaccination; The COI at month 6 was not significantly different from those at days 14 and 28. The results of the Pearson correlation test and Bland–Altman plot indicated a moderate correlation between Ichroma and iFlash (r = 0.592, p = 0.002). Conclusion: Neutralizing antibodies for Covid-19 were formed after day 14 and started to increase on day 28 and started to decrease in months 3 and 6. The levels of NAb for Covid-19 were measured with Ichroma and iFlash in roughly the same pattern and had a moderate positive correlation.

10aIchroma10aiFlash.10aNeutralizing Antibody1 aKahar, Hartono1 aPrasetyaningrum, Sari, Prabandari1 aFitriah, Munawaroh1 a1 aNugraha, Jusak uhttps://www.phcogj.com/article/1977