Abstract
Purpose: To determine whether the post-vaccination symptoms and symptom severities of the SARS-CoV-2 vaccine are associated with the anti-spike protein antibody (S antibody) titer.
Methods: Study participants were 287 university sports club members (244 males, 43 females; median age 20 years) who had received Moderna's vaccine. We identified, through participant-completed questionnaires, the presence or absence of vaccine-associated symptoms, including headache, chills/shivering, muscle pain, joint pain, injection-site pain, injection-site swelling, rash or itching, and sore throat. Severity was evaluated using a 4-grade score for fever and a 5-grade score for other side effects. Anti-nucleocapsid protein antibody (N antibody) and S antibody were measured using serum collected after the second vaccination.
Results: More than 40% of patients experienced malaise, muscle pain, and pain at the injection site after the first injection. Fever, malaise, headache, chills/shivering, arthralgia, and injection-site pain and swelling were significantly frequent in the second injection compared with the first. Comparing post-vaccination symptoms between N antibody-negative (207 [72.1%]) and -positive participants (80 [27.9%]), the frequency of fever, malaise, chills, and tremors was higher in the N antibody-positive group after the first dose. The S antibody titer in the N antibody-negative participants ranged between 2,815 and 5,283 U/mL (median, 3,970 U/mL). No clear association was observed between symptom severity and S antibody titer, nor between symptom scores other than fever and the S antibody titer.
Conclusion: Post-vaccination symptoms were more frequently observed after the second injection. Post-vaccination symptoms after the first injection were frequent among N antibody-positive participants. There was no relationship between the severity of vaccine-associated symptoms and the vaccine-induced S antibody titers.
