Antibody titer 6 months after the third dose of COVID-19 mRNA vaccination

Objectives: Administration of the third dose of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccine was initiated on December 1, 2021, in Japan. However, data on the long-term effects of this third vaccination remain scarce. Here, we examined the levels of SARS-CoV-2 antibodies in those who received the Pfizer BioNTech (BNT162b2) vaccine, 6 months after the third vaccination. Method(s): Samples from 40 healthy volunteers were used to measure SARS-CoV-2 antibodies with chemiluminescent assays against the receptor-binding domain (RBD) of the virus. Result(s): At 445 days after the first dose of BNT162b2, which is 180 days after the third vaccination, the mean anti-RBD IgG level was 159.4 AU/mL (SD 100.1 AU/mL), which was significantly higher than 144 days after the second vaccination, while mean anti-RBD IgM was baseline level (0.4 C.O.I.). The decline in IgG, 180 days after the third vaccination, was 74.1% (SD 16.1%), which was significantly lower than the 88.6% (SD 4.4%) decline observed 144 days after the second vaccination. Furthermore, we revealed that the reduction in IgG from 14 to 180 days after the third vaccination showed a significant inverse correlation with age, and the higher antibody response in younger participants at 14 days after the third vaccination disappeared at longer time points. Conclusion(s): The long-term durability of the IgG titer was significantly higher following the third vaccination compared with the second vaccination, and the reduction in IgG titer after the third vaccination inversely correlated with age.Copyright © 2022 the author(s), published by De Gruyter, Berlin/Boston.

COVID-19 transmission in dental and oral/maxillofacial surgical practice during pandemic: questionnaire survey in 51 university hospitals in Japan.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has become a major public health problem. Dental procedures that generate aerosols are considered to impose a high risk of infection; therefore, dental professionals, such as dentists and dental hygienists, may be at high risk of viral transmission. However, few studies have reported COVID-19 clusters in dental care settings. AIM: To investigate whether dental and oral/maxillofacial procedures are associated with the occurrence of COVID-19 clusters and measures taken to prevent nosocomial infection in dental clinics. METHODS: An online questionnaire survey on clinical activities (administrative control), infection control measures (environmental/engineering control, personal protective equipment, etc.), and confirmed or probable COVID-19 cases among patients and clinical staff was administered to the faculties of the dental and oral/maxillofacial surgical departments of university hospitals. FINDINGS: Fifty-one faculty members completed the questionnaire. All members were engaged in the treatment of dental and oral surgical outpatients and actively implemented standard precautions. Fourteen faculty members treated patients with COVID-19, but no infections transmitted from the patients to the medical staff were observed. In seven facilities, patients were found to have the infection after treatment (medical staff came in close contact), but there was no transmission from patients to medical staff. Four facilities had medical staff with infections, but none of them exhibited disease transmission from staff to patients. CONCLUSION: COVID-19 clusters are unlikely to occur in dental and oral surgical care settings if appropriate protective measures are implemented.

Assessment of COVID-19 mRNA vaccination titer and side effects in healthy volunteers

Objectives An effective vaccine against SARS-CoV-2 is essential to mitigate the COVID-19 pandemic. In these several months, a number of groups have started to report humoral responses and side effects after BNT162b2 vaccinations. Although these reports demonstrate the safety and efficacy, further studies are warranted to verify these findings. Here we examined the levels of SARS-CoV-2 antibodies in Japanese healthy volunteers who underwent BNT162b2 vaccine, to assess the humoral responses and side effects. Methods Forty-one healthy volunteers' samples were used for the measurement of SARS-CoV-2 antibodies with chemiluminescent assays against the Receptor Binding Domain (RBD) of the virus. We also measured the side effects of the vaccination. Results Although the levels of IgM varied, all participants were seronegative for IgM and IgG before vaccination, and both IgM and IgG were significantly increased after the vaccinations. We further analyzed the humoral responses in relation to age, and found that the IgG levels for 14 days and 35 days, and IgM levels for 14 days after vaccination showed clear declining trends with age. Commonly reported side effects in the participants were sore arm/pain (90.0%) after the first dose, and generalized weakness/fatigue (70.0%), fever (57.5%), and sore arm/pain (90.0%) after the second dose. Conclusions BNT162b2 vaccination generates sufficient production of IgG especially after the second dose, though the response decreases age-dependently. The high frequencies of generalized weakness/fatigue, fever, and sore arm/pain were not negligible, especially after the second dose. This may be associated with the age characteristics of the population.