Watsamon Jantarabenjakul1,2,3, Napaporn Chantasrisawad1,2,3, Thanyawee Puthanakit2,3, Supaporn Wacharapluesadee4, Nattiya Hirankarn5, Vichaya Ruenjaiman5, Leilani Paitoonpong1,6, Gompol Suwanpimolkul1,6, Pattama Torvorapanit1, Rakchanok Pradit1, Jiratchaya Sophonphan7, Opass Putcharoen1,6. 1. Thai Red Cross Emerging Infectious Diseases Clinical Center, King Chulalongkorn Memorial Hospital, Bangkok, Thailand. 2. Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. 3. Center of Excellence in Pediatric Infectious Diseases and Vaccines, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. 4. King Chulalongkorn Memorial Hospital, Bangkok, Thailand. 5. Center of Excellence in Immunology and Immune-Mediated Diseases, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. 6. Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. 7. The HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT), Thai Red Cross AIDS Research Centre, Bangkok, Thailand.
Abstract
BACKGROUND: Inactivated SARS-CoV-2 (CoronaVac®, Sinovac, or SV) and ChAdOx1 nCoV-19 (Vaxzevria®, Oxford-Astra Zeneca, or AZ) vaccines have been administered to the health care workers (HCWs). OBJECTIVE: To determine the short-term immune response after the SV and AZ vaccinations in HCWs. METHODS: In this prospective cohort study, HCWs who completed a 2-dose regimen of the SV or AZ were included. Immune response was evaluated by surrogate viral neutralization test (sVNT) and anti-SARS-CoV-2 total antibody. Blood samples were analyzed at 4 and 12 weeks after the complete vaccination. The primary outcome was the seroconversion rate at 4-weeks after complete immunization. RESULTS: Overall, 185 HCWs with a median (IQR) age of 40.5 (30.3-55.8) years (94 HCWs in the SV group and 91 in the AZ group) were included. At 4 weeks after completing the SV vaccination, 60.6% (95%CI: 50.0-70.6%) had seroconversion evaluated by sVNT (≥ 68% inhibition), comparable to the patients recovered from mild COVID-19 infection (69.0%), with a rapid reduction to 12.2% (95%CI: 6.3-20.8) at 12 weeks. In contrast, 85.7% (95%CI: 76.8-92.2%) HCWs who completed two doses of the AZ for 4 weeks had seroconversion, comparable to the COVID-19 pneumonia patients (92.5%), with a reduction to 39.2% (95%CI: 28.4-50.9%) at 12 weeks. When using the anti-SARS-CoV-2 total antibody level (≥ 132 U/ml) criteria, only 71.3% HCWs in the SV group had seroconversion, compared to 100% in the AZ group at 4 weeks. CONCLUSIONS: A rapid decline of short-term immune response in the HCWs after the SV vaccination indicates the need for a vaccine booster, particularly during the ongoing spreading of the SARS-CoV-2 variants of concern.
BACKGROUND: Inactivated SARS-CoV-2 (CoronaVac®, Sinovac, or SV) and ChAdOx1 nCoV-19 (Vaxzevria®, Oxford-Astra Zeneca, or AZ) vaccines have been administered to the health care workers (HCWs). OBJECTIVE: To determine the short-term immune response after the SV and AZ vaccinations in HCWs. METHODS: In this prospective cohort study, HCWs who completed a 2-dose regimen of the SV or AZ were included. Immune response was evaluated by surrogate viral neutralization test (sVNT) and anti-SARS-CoV-2 total antibody. Blood samples were analyzed at 4 and 12 weeks after the complete vaccination. The primary outcome was the seroconversion rate at 4-weeks after complete immunization. RESULTS: Overall, 185 HCWs with a median (IQR) age of 40.5 (30.3-55.8) years (94 HCWs in the SV group and 91 in the AZ group) were included. At 4 weeks after completing the SV vaccination, 60.6% (95%CI: 50.0-70.6%) had seroconversion evaluated by sVNT (≥ 68% inhibition), comparable to the patients recovered from mild COVID-19 infection (69.0%), with a rapid reduction to 12.2% (95%CI: 6.3-20.8) at 12 weeks. In contrast, 85.7% (95%CI: 76.8-92.2%) HCWs who completed two doses of the AZ for 4 weeks had seroconversion, comparable to the COVID-19 pneumonia patients (92.5%), with a reduction to 39.2% (95%CI: 28.4-50.9%) at 12 weeks. When using the anti-SARS-CoV-2 total antibody level (≥ 132 U/ml) criteria, only 71.3% HCWs in the SV group had seroconversion, compared to 100% in the AZ group at 4 weeks. CONCLUSIONS: A rapid decline of short-term immune response in the HCWs after the SV vaccination indicates the need for a vaccine booster, particularly during the ongoing spreading of the SARS-CoV-2 variants of concern.