tetano
Editor, Senior Moderator
Int J Infect Dis
. 2022 Feb 2;S1201-9712(22)00075-3.
doi: 10.1016/j.ijid.2022.01.068. Online ahead of print.
Evaluation of Immunogenicity by Pseudovirus Neutralization Assays for Coronavirus Disease 2019 (COVID-19) Variants after Primary and Booster Immunization
Hui Xie[SUP] 1 [/SUP], Xiaojing Wen[SUP] 1 [/SUP], Juan Li[SUP] 1 [/SUP], Weixin Chen[SUP] 1 [/SUP], Meng Chen[SUP] 1 [/SUP], Lichi Zhang[SUP] 1 [/SUP], Min Lv[SUP] 1 [/SUP], Shanshan Zhou[SUP] 1 [/SUP], Shuang Bai[SUP] 1 [/SUP], Wei Zhao[SUP] 1 [/SUP], Jian Wang[SUP] 1 [/SUP], Jiang Wu[SUP] 2 [/SUP]
Affiliations
Abstract
Objectives: To determine the status of immune responses after primary and booster immunization for coronavirus disease 2019 (COVID-19) variants and evaluate the differences in disease-resistance based upon titers of neutralizing antibodies (NAbs) against the variants.
Methods: Participants aged 18 - 59 y received two doses of inactivated COVID-19 vaccine, 14 days apart, and a booster dose after 12 m. Blood samples were collected before vaccination (baseline), 1 and 6 m after primary immunization, and at multiple instances within 21 d of booster dose. NAbs against the spike protein of Wuhan-Hu-1 and three variants were measured using pseudovirus neutralization assays.
Results: Out of 400 enrolled participants, 387 completed visits scheduled within 6 m of the second dose, and 346 participated received the booster dose in the follow-up research. After 1 m of primary immunization, geometric mean titers (GMTs) of NAbs peaked for Wuhan-Hu-1, while GMTs of other variants were < 30. After 6 m of primary immunization, GMTs of NAbs against all strains were < 30. After 3 d of booster immunization, GMTs were unaltered, seroconversion rates reached approximately 50% after 7 d, and GMTs of NAbs against all strains peaked at 14 d.
Conclusion: Two-dose of inactivated COVID-19 vaccine induced the formation of NAbs and memory-associated immune responses, and high titers of NAbs against the variants obtained after booster immunization may further improve the effectiveness of the vaccine.
Keywords: COVID-19 variant; inactivated COVID-19 vaccine; primary and booster immunization; pseudovirus neutralization assay.
. 2022 Feb 2;S1201-9712(22)00075-3.
doi: 10.1016/j.ijid.2022.01.068. Online ahead of print.
Evaluation of Immunogenicity by Pseudovirus Neutralization Assays for Coronavirus Disease 2019 (COVID-19) Variants after Primary and Booster Immunization
Hui Xie[SUP] 1 [/SUP], Xiaojing Wen[SUP] 1 [/SUP], Juan Li[SUP] 1 [/SUP], Weixin Chen[SUP] 1 [/SUP], Meng Chen[SUP] 1 [/SUP], Lichi Zhang[SUP] 1 [/SUP], Min Lv[SUP] 1 [/SUP], Shanshan Zhou[SUP] 1 [/SUP], Shuang Bai[SUP] 1 [/SUP], Wei Zhao[SUP] 1 [/SUP], Jian Wang[SUP] 1 [/SUP], Jiang Wu[SUP] 2 [/SUP]
Affiliations
- PMID: 35123028
- DOI: 10.1016/j.ijid.2022.01.068
Abstract
Objectives: To determine the status of immune responses after primary and booster immunization for coronavirus disease 2019 (COVID-19) variants and evaluate the differences in disease-resistance based upon titers of neutralizing antibodies (NAbs) against the variants.
Methods: Participants aged 18 - 59 y received two doses of inactivated COVID-19 vaccine, 14 days apart, and a booster dose after 12 m. Blood samples were collected before vaccination (baseline), 1 and 6 m after primary immunization, and at multiple instances within 21 d of booster dose. NAbs against the spike protein of Wuhan-Hu-1 and three variants were measured using pseudovirus neutralization assays.
Results: Out of 400 enrolled participants, 387 completed visits scheduled within 6 m of the second dose, and 346 participated received the booster dose in the follow-up research. After 1 m of primary immunization, geometric mean titers (GMTs) of NAbs peaked for Wuhan-Hu-1, while GMTs of other variants were < 30. After 6 m of primary immunization, GMTs of NAbs against all strains were < 30. After 3 d of booster immunization, GMTs were unaltered, seroconversion rates reached approximately 50% after 7 d, and GMTs of NAbs against all strains peaked at 14 d.
Conclusion: Two-dose of inactivated COVID-19 vaccine induced the formation of NAbs and memory-associated immune responses, and high titers of NAbs against the variants obtained after booster immunization may further improve the effectiveness of the vaccine.
Keywords: COVID-19 variant; inactivated COVID-19 vaccine; primary and booster immunization; pseudovirus neutralization assay.