Immunogenicity and immune-persistence of the CoronaVac or Covilo inactivated COVID-19 Vaccine: a 6-month population-based cohort study

Abstract

BackgroundOwing to the coronavirus disease 2019 (COVID-19) pandemic and the emergency use of different types of COVID-19 vaccines, there is an urgent need to consider the effectiveness and persistence of different COVID-19 vaccines.MethodsWe investigated the immunogenicity of CoronaVac and Covilo, two inactivated vaccines against COVID-19 that each contain inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The levels of neutralizing antibodies to live SARS-CoV-2 and the inhibition rates of neutralizing antibodies to pseudovirus, as well as the immunoglobulin (Ig)G and IgM responses towards the spike (S) and nucleocapsid (N) protein of SARS-CoV-2 at 180 days after two-dose vaccination were detected.ResultsThe CoronaVac and Covilo vaccines induced similar antibody responses. Regarding neutralizing antibodies to live SARS-CoV-2, 77.9% of the CoronaVac vaccine recipients and 78.3% of the Covilo vaccine recipients (aged 18–59 years) seroconverted by 28 days after the second vaccine dose. Regarding SARS-CoV-2-specific antibodies, 97.1% of the CoronaVac vaccine recipients and 95.7% of the Covilo vaccine recipients seroconverted by 28 days after the second vaccine dose. The inhibition rates of neutralizing antibody against a pseudovirus of the SARS-CoV-2 Delta variant were significantly lower compared with those against a pseudovirus of wildtype SARS-CoV-2. Associated with participant characteristics and antibody levels, persons in the older age group and with basic disease, especially a chronic respiratory disease, tended to have lower anti-SARS-CoV-2 antibody seroconversion rates.ConclusionAntibodies that were elicited by these two inactivated COVID-19 vaccines appeared to wane following their peak after the second vaccine dose, but they persisted at detectable levels through 6 months after the second vaccine dose, and the effectiveness of these antibodies against the Delta variant of SARS-CoV-2 was lower than their effectiveness against wildtype SARS-CoV-2, which suggests that attention must be paid to the protective effectiveness, and its persistence, of COVID-19 vaccines on SARS-CoV-2 variants.

Application of Traditional Vaccine Development Strategies to SARS-CoV-2

“…Therefore, studies have also evaluated whether booster doses would provide additional protection to individuals vaccinated with CoronaVac. This strategy is supported by the fact that the antibody response elicited by CoronaVac has been found to wane following the second dose, though it was still detected 6 months out ( 83 ). A phase I/II clinical trial of CoronaVac in an elderly cohort (adults 60 years and older) in China determined that by 6 to 8 months following the second dose, nAb titers were detected below the seropositive cutoff ( 84 ).…”

“…Studies have also investigated expected differences in real-world effectiveness of Covilo given the continuing evolution of SARS-CoV-2. The antibody response elicited by Covilo was found to wane, but to still be detectable, by 6 months following the second dose ( 83 ). One study showed that the Alpha variant exhibited very little resistance to neutralization by sera of those immunized with Covilo, but the Beta variant was more resistant to neutralization by almost a factor of 3 ( 81 ).…”

Comparison of Biological, Pharmacological Characteristics, Indications, Contraindications, Efficacy, and Adverse Effects of Inactivated Whole-Virus COVID-19 Vaccines Sinopharm, CoronaVac, and Covaxin: An Observational Study

“…Moreover, the mean efficacy of Covaxin is 61.80% against all variants of COVID-19 (Table 3; Figures 2 and 3). Neutralizing antibodies to live SARS-CoV-2; 77.9% seroconverted was by 28 days after the second dose [17] Two doses of vaccines with an interval of 28 days showed 95.0% seropositivity to anti-spike antibodies. [18,19] Local adverse effects Pain at the injection site, redness, [20] Injection site pain (41.5%) [21] Injection site pain, swelling, redness, and itching [15].…”

The dynamics and determinants of specific systemic and mucosal antibody responses to SARS-CoV-2 in three adult cohorts in the Ecuadorian Andes: a study protocol

“…1,29,30 In contrast, specific IgG antibodies following vaccination against SARS-CoV-2 are detectable from about a week following the first dose and peak at approximately 30 days after the second dose, remaining detectable for 3-6 months. 31,32 For example, a cross-sectional study in 56,261 Chilean individuals reported an IgG seroprevalence of 28.1% three weeks after the first dose and 77.4% four weeks after the second dose of the CoronaVac vaccine; and a prevalence of 79.4% three weeks after the first dose and 96.5% four weeks after the second dose of the BNT162b2 Pfizer vaccine. 7 In healthcare workers (HCW) receiving the BNT162b2 Pfizer vaccine, a study showed that median serum levels of antibodies reached a peak 1 month after the second dose and were 37% and 57% lower at 3 and 6 months, respectively.…”