Safety and immunogenicity of inactivated COVID-19 vaccine in health care workers.

Effective vaccines are essential for controlling the coronavirus disease 2019 (COVID-19) pandemic. CoronaVac, which is an inactivated virus vaccine, was the first imported COVID-19 vaccine in Thailand. To investigate the safety and immunogenicity of CoronaVac within the Thai population, we conducted a prospective cohort study among health care workers aged 18-59 years, who received a 2-dose regimen of CoronaVac 21 days apart between March and April 2021 at the hospital in Samut Sakhon, Thailand. We recruited 185 participants with a mean age of 32 years. Total antibodies against receptor-binding domain (RBD) and immunoglobulin G (IgG) against nucleocapsid (N) protein of SARS-CoV-2 were tested. Total antibodies against RBD were negative before immunization. One volunteer was positive for N, although negative for the RBD antibodies. The seroconversion rate of total antibodies against RBD after the first CoronaVac dose was 67% with a Geometric mean concentration (GMC) of 1.98 U/ml. Following CoronaVac dose 2, the seroconversion rate increased to 100% with a GMC of 92.9 U/ml. The seroconversion rates of IgG against N protein were 1% after dose 1 and 62.8% after dose 2. The overall incidence of adverse reactions was 59.5%. Injection-site pain was the most common local adverse event (52.4%), while myalgia was the most common systemic adverse event (31.9%). No serious adverse events were observed. A 0-21 days, 2-dose CoronaVac regimen appears safe, inducing a satisfactory response compared with convalescent serum obtained 4-6 weeks postnatural infection. Antibody responses after 2-dose CoronaVac were comparable to the convalescent plasma but waned rapidly after 3 months. Therefore, we recommend 2-dose CoronaVac administration with possible booster doses.

Skin Prick Test Versus Phadiatop as a Tool for Diagnosis of Allergic Rhinitis in Children.

BACKGROUND: Skin prick test (SPT) or Phadiatop, a multi-allergen IgE screening test, was used as a tool for detecting aeroallergen sensitization. OBJECTIVE: To compare SPT and Phadiatop as a tool for diagnosis allergic rhinitis (AR) using the nasal provocation test (NPT) as a comparative standard. METHODS: Children aged 5-18 years with rhinitis symptoms more than 6 times in the past year were enrolled. SPT to 13 common aeroallergens, serum for Phadiatop, and NPT to Dermatophagoides pteronyssinus (Der p) were performed. NPT to mixed cockroach (CR) were performed in children who had CR sensitization and negative NPT to Der p. Children who had a disagreement between the result of SPT and Phadiatop or having negative results were evaluated for specific IgE (sIgE) to common aeroallergens. RESULTS: One hundred-forty children were enrolled with the mean age of 9.8 ± 3 years, 56% were male. Of 92 children (65.7%) with positive SPT to any aeroallergens, 88 children (95.6%) were sensitized to house dust mite (HDM). NPT showed positive results in 97 children (69.3%). Of 48 children who showed negative SPT, 4 children (8.3%) had sIgE to aeroallergens but NPT was positive in 1 child. Eighty-eight children (62.9%) had positive tests for Phadiatop and 4 (4.5%) of them had negative results for NPT to Der p. Among 52 children who had negative results for Phadiatop, 4 children (7.6%) had sIgE to aeroallergens but NPT was positive in 2 children (3.8%). SPT and Phadiatop showed 94.2% agreement: with Kappa 0.876, p < 0.001. Using NPT as a comparative standard for diagnosis for AR, SPT showed a sensitivity of 89.6% and specificity of 88.3% and Phadiatop provided the sensitivity of 88.6% and specificity of 95.3%. CONCLUSIONS: SPT to aeroallergen and Phadiatop have good and comparable sensitivity and specificity for the diagnosis of AR in children.