Immunogenicity and safety of a third dose of CoronaVac, and immune persistence of a two-dose schedule, in healthy adults: interim results from two single-centre, double-blind, randomised, placebo-controlled phase 2 clinical trials

Relative vaccine effectiveness against Delta and Omicron COVID-19 after homologous inactivated vaccine boosting: a retrospective cohort study

ObjectiveTwo COVID-19 outbreaks occurred in Henan province in early 2022-one was a Delta variant outbreak and the other was an Omicron variant outbreak. COVID-19 vaccines used at the time of the outbreak were inactivated, 91.8%; protein subunit, 7.5%; and adenovirus5-vectored, 0.7% vaccines. The outbreaks provided an opportunity to evaluate variant-specific breakthrough infection rates and relative protective effectiveness of homologous inactivated COVID-19 vaccine booster doses against symptomatic infection and pneumonia.

DESIGN

Retrospective cohort study METHODS: We evaluated relative vaccine effectiveness (rVE) with a retrospective cohort study of close contacts of infected individuals using a time-dependent Cox regression model. Demographic and epidemiologic data were obtained from the local Centers for Disease Control and Prevention; clinical and laboratory data were obtained from COVID-19-designated hospitals. Vaccination histories were obtained from the national COVID-19 vaccination dataset. All data were linked by national identification number.

RESULTS

Among 784 SARS-CoV-2 infections, 379 (48.3%) were caused by Delta and 405 (51.7%) were caused by Omicron, with breakthrough rates of 9.9% and 17.8%, respectively. Breakthrough rates among boosted individuals were 8.1% and 4.9%. Compared with subjects who received primary vaccination series ≥180 days before infection, Cox regression modelling showed that homologous inactivated booster vaccination was statistically significantly associated with protection from symptomatic infection caused by Omicron (rVE 59%; 95% CI 13% to 80%) and pneumonia caused by Delta (rVE 62%; 95% CI 34% to 77%) and Omicron (rVE 87%; 95% CI 3% to 98%).

CONCLUSIONS

COVID-19 vaccination in China provided good protection against symptomatic COVID-19 and COVID-19 pneumonia caused by Delta and Omicron variants. Protection declined 6 months after primary series vaccination but was restored by homologous inactivated booster doses given 6 months after the primary series.

Safety and immunogenicity of heterologous recombinant protein subunit vaccine (ZF2001) booster against COVID-19 at 3-9-month intervals following two-dose inactivated vaccine (CoronaVac)

BACKGROUND

In response to SARS-CoV-2 mutations and waning antibody levels after two-dose inactivated vaccines, we assessed whether a third dose of recombinant protein subunit vaccine (ZF2001) boosts immune responses.

METHODS

An open-label single-center non-random trial was conducted on people aged 18 years and above at five sites in China. All participants received a two-dose inactivated vaccine (CoronaVac) as their prime doses within 3-9 months of the trial. Primary outcomes were safety and immunogenicity, primarily the geometric mean titers (GMTs) of neutralizing antibodies to live wildtype SARS-CoV-2.

RESULTS

A total of 480 participants (median age, 51; range 21-84 years) previously vaccinated with two-dose CoronaVac received a third booster dose of ZF2001 3-4, 5-6, or 7-9-months later. The overall incidence of adverse reactions within 30 days after vaccination was 5.83% (28/480). No serious adverse reactions were reported after the third dose of ZF2001. GMTs in the 3-4-, 5-6-, and 7-9-month groups before vaccination were 3.96, 4.60, and 3.78, respectively. On Day 14, GMTs increased to 33.06, 47.51, and 44.12, respectively. After the booster, GMTs showed no significant difference among the three prime-boost interval groups (all P>0.05). Additionally, GMTs in older adults were lower than those in younger adults on Day 14 for the three groups (P=0.0005, P<0.0001, and P<0.0001).

CONCLUSION

Heterologous boosting with ZF2001 was safe and immunogenic, and prime-boost intervals did not affect the immune response. The immune response was weaker in older than younger adults.

Efficacy, Immunogenicity, and Safety of the Two-Dose Schedules of TURKOVAC versus CoronaVac in Healthy Subjects: A Randomized, Observer-Blinded, Non-Inferiority Phase III Trial

We present the interim results of the efficacy, immunogenicity, and safety of the two-dose schedules of TURKOVAC versus CoronaVac. This was a randomized, observer-blinded, non-inferiority trial (NCT04942405). Volunteers were 18-55 years old and randomized at a 1:1 ratio to receive either TURKOVAC or CoronaVac at Day 0 and Day 28, both of which are 3 μg/0.5 mL of inactivated severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) adsorbed to aluminum hydroxide. The primary efficacy outcome was the prevention of polymerase chain reaction (PCR)-confirmed symptomatic coronavirus disease 2019 (COVID-19) at least 14 days after the second dose in the modified per-protocol (mPP) group. Safety analyses were performed in the modified intention-to-treat (mITT) group. Between 22 June 2021 and 7 January 2022, 1290 participants were randomized. The mITT group consisted of 915 participants, and the mPP group consisted of 732 participants. During a median follow-up of 90 (IQR 86-90) days, the relative risk reduction with TURKOVAC compared to CoronaVac was 41.03% (95% CI 12.95-60.06) for preventing PCR-confirmed symptomatic COVID-19. The incidences of adverse events (AEs) overall were 58.8% in TURKOVAC and 49.7% in CoronaVac arms (p = 0.006), with no fatalities or grade four AEs. TURKOVAC was non-inferior to CoronaVac in terms of efficacy and demonstrated a good safety and tolerability profile.

Plaque-neutralizing antibody to BA.2.12.1, BA.4 and BA.5 in individuals with three doses of BioNTech or CoronaVac vaccines, natural infection and breakthrough infection

BACKGROUND

BA.2.12.1, BA.4 and BA.5 subvariants of SARS-CoV-2 variant-of-concern (VOC) Omicron (B.1.1.529) are spreading globally. They demonstrate higher transmissibility and immune escape.

OBJECTIVES

Determine BA.2.12.1, BA.4 and BA.5 virus plaque reduction neutralization test (PRNT) antibody titres in individuals recently vaccinated with BNT162b2 (n = 20) or CoronaVac (n = 20) vaccines or those convalescent from ancestral wild- type (WT) SARS-CoV-2 (n = 20) or BA.2 infections with (n = 17) or without (n = 7) prior vaccination.

RESULTS

Relative to neutralization of the WT virus, those vaccinated with BNT162b2 had 4.8, 3.4, 4.6, 11.3 and 15.5-fold reductions of geometric mean antibody titres (GMT) to BA.1, BA.2, BA.2.12.1, BA.4 and BA.5 viruses, respectively. Similarly, those vaccinated with CoronaVac had 8.0, 7.0, 11.8, 12.0 and 12.0 fold GMT reductions and those with two doses of CoronaVac boosted by BNT162b2 had 6.1, 6.7, 6,3, 13.0 and 21.2 fold GMT reductions to these viruses, respectively. Vaccinated individuals with BA.2 breakthrough infections had higher GMT antibody levels vs. BA.4 (36.9) and BA.5 (36.9) than unvaccinated individuals with BA.2 infections (BA.4 GMT 8.2; BA.5 GMT 11.0).

CONCLUSIONS

BA.4 and BA.5 subvariants were less susceptible to BNT162b2 or CoronaVac vaccine elicited antibody neutralization than subvariants BA.1, BA.2 and BA.2.12.1. Nevertheless, three doses BNT162b2 or booster of BNT162b2 following two doses of CoronaVac elicited detectable BA.4 and BA.5 neutralizing antibody responses while those vaccinated with three doses of CoronaVac largely fail to do so. BA.2 infections in vaccinated individuals led to higher levels of BA.4 or BA.5 neutralizing antibody compared to those who were vaccine-naive.

Short-term safety and immunogenicity of inactivated and peptide-based SARS-CoV-2 vaccines in patients with endocrine-related cancer

Background

The aim of this study was to explore the short-term safety and immunogenicity of inactivated and peptide-based SARS-CoV-2 vaccines in patients with endocrine-related cancer (ER).

Methods

Eighty-eight patients with ER cancer and 82 healthy controls who had completed a full course of inactivated or peptide-based SARS-CoV-2 vaccines were recruited. Adverse events (AEs) were recorded. Responses to receptor-binding domain IgG antibody (anti-RBD-IgG), neutralizing antibodies (NAbs) and RBD+ memory B cells (MBCs) were evaluated.

Results

Approximately 26.14% (23/88) of patients with ER cancer reported AEs within 7 days, which was comparable to that reported by healthy controls (24.39%, 20/82). Both the overall seroprevalence of anti-RBD-IgG and NAbs was obviously lower in the cancer group (70.45% vs. 86.59%, P &lt; 0.05; 69.32% vs. 82.93%, P &lt; 0.05, respectively). Anti-RBD-IgG and NAbs titers exhibited similar results, and dropped gradually over time. Patients with ongoing treatment had an attenuated immune response, especially in patients receiving active chemotherapy. The frequency of overall RBD+ MBCs was similar between the two groups, but the percentage of active MBCs was remarkably reduced in patients with ER cancer. Unlike antibody titers, MBCs responses were relatively constant over time.

Conclusion

Inactivated and peptide-based COVID-19 vaccines were well tolerated, but with lower immunogenicity for ER cancer patients. More intensive antibody monitoring and timely booster immunization is recommended for patients with ER cancer presenting disordered subpopulations of RBD+ MBCs.

Observational study of antibody levels after second and third SARS-CoV-2 vaccinations in medical workers

BACKGROUND

Countries around the world are actively promoting vaccination against COVID-19. We observed the changes in serum neutralizing antibody titers in medical workers vaccinated with inactivated COVID-19 vaccine, in order to explore the necessity of a third dose of vaccination.

METHODS

A total of 62 medical workers in our hospital were observed. Novel coronavirus neutralizing antibody titers in serum were detected by ELISA (enzyme-linked immunoassay). Neutralizing antibody tests followed in four batches according to the different time periods after three vaccinations. Sixty-two observers participated in the first batch of testing for neutralizing antibody, and 18 of them participated in all four batches. Fasting venous blood was taken from all the participants in the morning to detect serum neutralizing antibody titers.

RESULTS

Sixty-two medical workers were divided into age groups of 21-30, 31-40, and >40 years, and the antibody titer in the oldest group was significantly lower than that in youngest group (p = 0.0137). There was a gradual decrease in antibody titers over time at around 1, 3, and 6 months after the second dose of vaccine (p < 0.0001). The antibody positive rate also decreased gradually (p = 0.0003). The neutralizing antibody titer around 1 month after the third dose was significantly increased (p < 0.0001). Unexpectedly, three participants with negative neutralizing antibody after the first and second dose produced neutralizing antibody with a measurable titer after the third dose.

CONCLUSIONS

The neutralizing antibody titer in serum increased significantly after the third dose of vaccine. A third immunization even produced neutralizing antibody in previously negative individuals.

COVID-19 vaccine update: vaccine effectiveness, SARS-CoV-2 variants, boosters, adverse effects, and immune correlates of protection

Coronavirus Disease 2019 (COVID-19) has been the most severe public health challenge in this century. Two years after its emergence, the rapid development and deployment of effective COVID-19 vaccines have successfully controlled this pandemic and greatly reduced the risk of severe illness and death associated with COVID-19. However, due to its ability to rapidly evolve, the SARS-CoV-2 virus may never be eradicated, and there are many important new topics to work on if we need to live with this virus for a long time. To this end, we hope to provide essential knowledge for researchers who work on the improvement of future COVID-19 vaccines. In this review, we provided an up-to-date summary for current COVID-19 vaccines, discussed the biological basis and clinical impact of SARS-CoV-2 variants and subvariants, and analyzed the effectiveness of various vaccine booster regimens against different SARS-CoV-2 strains. Additionally, we reviewed potential mechanisms of vaccine-induced severe adverse events, summarized current studies regarding immune correlates of protection, and finally, discussed the development of next-generation vaccines.

Cost-Effectiveness of COVID-19 Sequential Vaccination Strategies in Inactivated Vaccinated Individuals in China

To effectively prevent and control the COVID-19 pandemic, countries have adopted a booster vaccination strategy. This study aimed to estimate the cost-effectiveness of sequential booster COVID-19 vaccination compared to two-dose inactivated vaccination in China from a societal perspective. A Markov model was developed to estimate the cost-effectiveness of sequential vaccination, including two doses of an inactivated vaccine followed by a booster shot of an inactivated vaccine, adenovirus vectored vaccine, protein subunit vaccine, or mRNA vaccine. The incremental effects of a booster shot with an inactivated vaccine, protein subunit vaccine, adenovirus vectored vaccine, and mRNA vaccine were 0.0075, 0.0110, 0.0208, and 0.0249 QALYs and saved costs of US$163.96, US$261.73, US$583.21, and US$724.49, respectively. Under the Omicron virus pandemic, the sequential vaccination among adults and the elderly (aged 60-69, 70-79, over 80) was consistently cost-saving, and a booster shot of the mRNA vaccine was more cost-saving. The results indicate that the sequential vaccination strategy is cost-effective in addressing the COVID-19 pandemic, and improving vaccination coverage among the elderly is of great importance in avoiding severe cases and deaths.

Immune Persistence against SARS-CoV-2 after Primary and Booster Immunization in Humans: A Large-Scale Prospective Cohort Study

Amid the ongoing global COVID-19 pandemic, limited literature exists on immune persistence after primary immunization and the immunogenic features of booster vaccines administered at different time intervals. Therefore, this study aimed to determine the immune attenuation of neutralizing antibodies against the SARS-CoV-2 wild-type strain, and Delta and Omicron variants 12 months after the primary administration of the COVID-19 inactivated vaccine and evaluate the immune response after a booster administration at different time intervals. A total of 514 individuals were followed up after primary immunization and were vaccinated with a booster. Neutralizing antibodies against the wild-type strain and Delta and Omicron variant spike proteins were measured using pseudovirus neutralization assays. The geometric mean titers (GMTs) after the primary and booster immunizations were 12.09 and 61.48 for the wild-type strain, 11.67 and 40.33 for the Delta variant, and 8.51 and 29.31 for the Omicron variant, respectively. The GMTs against the wild-type strain declined gradually during the 12 months after the primary immunization, and were lower against the two variants. After implementing a booster immunization with a 6 month interval, the GMTs against the wild-type strain were higher than those obtained beyond the 7 month interval; however, the GMTs against the two variants were not statistically different across 3–12 month intervals. Overall, SARS-CoV-2 variants showed remarkable declines in immune persistence, especially against the Omicron variant. The booster administration interval could be shortened to 3 months in endemic areas of the Omicron variant, whereas an appropriate prolonging of the booster administration interval did not affect the booster immunization effect.

A comparative characterization of SARS-CoV-2-specific T cells induced by mRNA or inactive virus COVID-19 vaccines

Unlike mRNA vaccines based only on the spike protein, inactivated severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccines should induce a diversified T cell response recognizing distinct structural proteins. Here, we perform a comparative analysis of SARS-CoV-2-specific T cells in healthy individuals following vaccination with inactivated SARS-CoV-2 or mRNA vaccines. Relative to spike mRNA vaccination, inactivated vaccines elicit a lower magnitude of spike-specific T cells, but the combination of membrane, nucleoprotein, and spike-specific T cell response is quantitatively comparable with the sole spike T cell response induced by mRNA vaccine, and they efficiently tolerate the mutations characterizing the Omicron lineage. However, this multi-protein-specific T cell response is not mediated by a coordinated CD4 and CD8 T cell expansion but by selective priming of CD4 T cells. These findings can help in understanding the role of CD4 and CD8 T cells in the efficacy of the different vaccines to control severe COVID-19 after Omicron infection.

Effectiveness of an inactivated Covid-19 vaccine with homologous and heterologous boosters against Omicron in Brazil

The effectiveness of inactivated vaccines (VE) against symptomatic and severe COVID-19 caused by omicron is unknown. We conducted a nationwide, test-negative, case-control study to estimate VE for homologous and heterologous (BNT162b2) booster doses in adults who received two doses of CoronaVac in Brazil in the Omicron context. Analyzing 1,386,544 matched-pairs, VE against symptomatic disease was 8.6% (95% CI, 5.6-11.5) and 56.8% (95% CI, 56.3-57.3) in the period 8-59 days after receiving a homologous and heterologous booster, respectively. During the same interval, VE against severe Covid-19 was 73.6% (95% CI, 63.9-80.7) and 86.0% (95% CI, 84.5-87.4) after receiving a homologous and heterologous booster, respectively. Waning against severe Covid-19 after 120 days was only observed after a homologous booster. Heterologous booster might be preferable to individuals with completed primary series inactivated vaccine.

Three-Dose Primary Series of Inactivated COVID-19 Vaccine for Persons Living with HIV, Hong Kong

In a cohort of persons living with HIV in Hong Kong, surrogate virus neutralization testing for COVID-19 yielded a median level of 89% after the third dose of an inactivated COVID-19 vaccine, compared with 37% after the second dose. These results support using a 3-dose primary series for enhanced immune protection.

The impact of CoronaVac on the neutralization breadth and magnitude of the antibody response to SARS-CoV-2 viruses

Although immune response enhancement has been reported after primary and booster vaccines of CoronaVac, neutralization breadth of SARS-CoV-2 variants is still unclear. In the present study, we examined the neutralization magnitude and breadth of SARS-CoV-2 variants including Beta (B.1.351), Delta (B.1.617.2) and Omicron (B.1.1.529) in 33 convalescent COVID-19 patients and a cohort of 55 medical staff receiving primary CoronaVac vaccines and an additional homologous booster dose. Results showed that, as compared with the two-dose primary vaccination, the homologous booster dose achieved 2.24-, 3.98-, 4.58- and 2.90-fold increase in neutralization titer against wild-type, Beta, Delta, and Omicron, respectively. After booster dose, neutralization titer reduction for variants was less than that after the primary vaccine or that for convalescents. The proportion of recipients able to neutralize 2 or more variants increased from 36.36% post the primary vaccination to 87.27% after the booster. Significant increase in neutralization breadth of 1.24 (95% confidence interval (CI), 0.89–1.59) variants was associated with a log₁₀ increase in neutralization titer against the wild-type. In addition, anti-RBD IgG level was identified as an excellent surrogate for positive neutralization of SARS-CoV-2 and neutralization breadth of variants. These findings highlight the value of an additional homologous CoronaVac dose in broadening the cross-neutralization against SARS-CoV-2 variants, and are critical for informing the booster dose vaccination efforts.

Efficacy, immunogenicity and safety of COVID-19 vaccines in older adults: a systematic review and meta-analysis

Background

Older adults are more susceptible to severe health outcomes for coronavirus disease 2019 (COVID-19). Universal vaccination has become a trend, but there are still doubts and research gaps regarding the COVID-19 vaccination in the elderly. This study aimed to investigate the efficacy, immunogenicity, and safety of COVID-19 vaccines in older people aged ≥ 55 years and their influencing factors.

Methods

Randomized controlled trials from inception to April 9, 2022, were systematically searched in PubMed, EMBASE, the Cochrane Library, and Web of Science. We estimated summary relative risk (RR), rates, or standardized mean difference (SMD) with 95% confidence interval (CI) using random-effects meta-analysis. This study was registered with PROSPERO (CRD42022314456).

Results

Of the 32 eligible studies, 9, 21, and 25 were analyzed for efficacy, immunogenicity, and safety, respectively. In older adults, vaccination was efficacious against COVID-19 (79.49%, 95% CI: 60.55−89.34), with excellent seroconversion rate (92.64%, 95% CI: 86.77−96.91) and geometric mean titer (GMT) (SMD 3.56, 95% CI: 2.80−4.31) of neutralizing antibodies, and provided a significant protection rate against severe disease (87.01%, 50.80−96.57). Subgroup and meta-regression analyses consistently found vaccine types and the number of doses to be primary influencing factors for efficacy and immunogenicity. Specifically, mRNA vaccines showed the best efficacy (90.72%, 95% CI: 86.82−93.46), consistent with its highest seroconversion rate (98.52%, 95% CI: 93.45−99.98) and GMT (SMD 6.20, 95% CI: 2.02−10.39). Compared to the control groups, vaccination significantly increased the incidence of total adverse events (AEs) (RR 1.59, 95% CI: 1.38−1.83), including most local and systemic AEs, such as pain, fever, chill, etc. For inactivated and DNA vaccines, the incidence of any AEs was similar between vaccination and control groups (p &gt; 0.1), while mRNA vaccines had the highest risk of most AEs (RR range from 1.74 to 7.22).

Conclusion

COVID-19 vaccines showed acceptable efficacy, immunogenicity and safety in older people, especially providing a high protection rate against severe disease. The mRNA vaccine was the most efficacious, but it is worth surveillance for some AEs it caused. Increased booster coverage in older adults is warranted, and additional studies are urgently required for longer follow-up periods and variant strains.

Factors associated with neutralizing antibody levels induced by two inactivated COVID-19 vaccines for 12 months after primary series vaccination

Background

BBIBP-CorV and CoronaVac inactivated COVID-19 vaccines are widely-used, World Health Organization-emergency-listed vaccines. Understanding antibody level changes over time after vaccination is important for booster dose policies. We evaluated neutralizing antibody (nAb) titers and associated factors for the first 12 months after primary-series vaccination with BBIBP-CorV and CoronaVac.

Methods

Our study consisted of a set of cross-sectional sero-surveys in Zhejiang and Shanxi provinces, China. In 2021, we enrolled 1,527 consenting 18-59-year-olds who received two doses of BBIBP-CorV or CoronaVac 1, 3, 6, 9, or 12 months earlier and obtained blood samples and demographic and medical data. We obtained 6-month convalescent sera from 62 individuals in Hebei province. Serum nAb titers were measured by standard micro-neutralization cytopathic effect assay in Vero cells with ancestral SARS-CoV-2 strain HB01. We used the first WHO International Standard (IS) for anti-SARS-CoV-2 immunoglobulin (NIBSC code 20/136) to standardized geometric mean concentrations (IU/mL) derived from the nAb geometric mean titers (GMT over 1:4 was considered seropositive). We analyzed nAb titer trends using Chi-square and factors related to nAb titers with logistic regression and linear models.

Results

Numbers of subjects in each of the five month-groupings ranged from 100 to 200 for each vaccine and met group-specific target sample sizes. Seropositivity rates from BBIBP-CorV were 98.0% at 1 month and 53.5% at 12 months, and GMTs were 25.0 and 4.0. Respective seropositivity rates from CoronaVac were 90.0% and 62.5%, and GMTs were 20.2 and 4.1. One-, three-, six-, nine-, and twelve-month GMCs were 217.2, 84.1, 85.7, 44.6, and 10.9 IU/mL in BBIBP-CorV recipients and 195.7, 94.6, 51.7, 27.6, and 13.4 IU/mL in CoronaVac recipients. Six-month convalescent seropositivity was 95.2%; GMC was 108.9 IU/mL. Seropositivity and GMCs were associated with age, sex, and time since vaccination.

Conclusions

Neutralizing Ab levels against ancestral SARS-CoV-2 from BBIBP-CorV or CoronaVac vaccination were similar and decreased with increasing time since vaccination; over half of 12-month post-vaccination subjects were seropositive. Seropositivity and GMCs from BBIBP-CorV and CoronaVac six and nine months after vaccination were similar to or slightly lower than in six-month convalescent sera. These real-world data suggest necessity of six-month booster doses.

Humoral responses after inactivated COVID-19 vaccination in individuals with and without prior SARS-CoV-2 infection: A prospective cohort study

We evaluated and compared humoral immune responses after inactivated coronavirus disease 2019 (COVID-19) vaccination among naïve individuals, asymptomatically infected individuals, and recovered patients with varying severity. In this multicenter, prospective cohort study, blood samples from 666 participants were collected before and after 2 doses of inactivated COVID-19 vaccination. Among 392 severe acute respiratory syndrome coronavirus 2-naïve individuals, the seroconversion rate increased significantly from 51.8% (median antispike protein pan-immunoglobulins [S-Igs] titer: 0.8 U/ml) after the first dose to 96% (median S-Igs titer: 79.5 U/ml) after the second dose. Thirty-two percent of naïve individuals had detectable neutralizing antibodies (NAbs) against the original strain but all of them lost neutralizing activity against the Omicron variant. In 274 individuals with natural infection, humoral immunity was significantly improved after a single vaccine dose, with median S-Igs titers of 596.7, 1176, 1086.5, and 1828 U/ml for asymptomatic infections, mild cases, moderate cases, and severe/critical cases, respectively. NAb titers also improved significantly. However, the second dose did not substantially increase antibody levels. Although a booster dose is needed for those without infection, our findings indicate that recovered patients should receive only a single dose of the vaccine, regardless of the clinical severity, until there is sufficient evidence to confirm the benefits of a second dose.

Comparison of the Effectiveness and Safety of Heterologous Booster Doses with Homologous Booster Doses for SARS-CoV-2 Vaccines: A Systematic Review and Meta-Analysis

As vaccine resources were distributed unevenly worldwide, sometimes there might have been shortages or delays in vaccine supply; therefore, considering the use of heterogeneous booster doses for Coronavirus disease 2019 (COVID-19) might be an alternative strategy. Therefore, we aimed to review the data available to evaluate and compare the effectiveness and safety of heterologous booster doses with homologous booster doses for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines. We searched relevant studies up to 27 April 2022. Random-effects inverse variance models were used to evaluate the vaccine effectiveness (VE) and its 95% confidence interval (CI) of COVID-19 outcomes and odds ratio (OR) and its CI of safety events. The Newcastle-Ottawa quality assessment scale and Cochrane Collaboration's tool were used to assess the quality of the included cohort studies. A total of 23 studies involving 1,726,506 inoculation cases of homologous booster dose and 5,343,580 inoculation cases of heterologous booster dose was included. The VE of heterologous booster for the prevention of SARS-CoV-2 infection (VEheterologous = 96.10%, VEhomologous = 84.00%), symptomatic COVID-19 (VEheterologous = 56.80%, VEhomologous = 17.30%), and COVID-19-related hospital admissions (VEheterologous = 97.40%, VEhomologous = 93.20%) was higher than homologous booster. Compared with homologous booster group, there was a higher risk of fever (OR = 1.930, 95% CI, 1.199-3.107), myalgia (OR = 1.825, 95% CI, 1.079-3.089), and malaise or fatigue (OR = 1.745, 95% CI, 1.047-2.906) within 7 days after boosting, and a higher risk of malaise or fatigue (OR = 4.140, 95% CI, 1.729-9.916) within 28 days after boosting in heterologous booster group. Compared with homologous booster group, geometric mean neutralizing titers (GMTs) of neutralizing antibody for different SARS-CoV-2 variants and response rate of antibody and gama interferon were higher in heterologous booster group. Our findings suggested that both homologous and heterologous COVID-19 booster doses had great effectiveness, immunogenicity, and acceptable safety, and a heterologous booster dose was more effective, which would help make appropriate public health decisions and reduce public hesitancy in vaccination.

A comprehensive analysis of the efficacy and effectiveness of COVID-19 vaccines

It is urgently needed to update the comprehensive analysis about the efficacy or effectiveness of COVID-19 vaccines especially during the COVID-19 pandemic caused by SARS-CoV-2 Delta and Omicron variants. In general, the current COVID-19 vaccines showed a cumulative efficacy of 66.4%, 79.7%, and 93.6% to prevent SARS-CoV-2 infection, symptomatic COVID-19, and severe COVID-19, respectively, but could not prevent the asymptomatic infection of SARS-CoV-2. Furthermore, the current COVID-19 vaccines could effectively prevent COVID-19 caused by the Delta variant although the incidence of breakthrough infection of the SARS-CoV-2 Delta variant increased when the intervals post full vaccination extended, suggesting the waning effectiveness of COVID-19 vaccines. In addition, one-dose booster immunization showed an effectiveness of 74.5% to prevent COVID-19 caused by the Delta variant. However, current COVID-19 vaccines could not prevent the infection of Omicron sub-lineage BA.1.1.529 and had about 50% effectiveness to prevent COVID-19 caused by Omicron sub-lineage BA.1.1.529. Furthermore, the effectiveness was 87.6% and 90.1% to prevent severe COVID-19 and COVID-19-related death caused by Omicron sub-lineage BA.2, respectively, while one-dose booster immunization could enhance the effectiveness of COVID-19 vaccines to prevent the infection and COVID-19 caused by Omicron sub-lineage BA.1.1.529 and sub-lineage BA.2. Two-dose booster immunization showed an increased effectiveness of 81.8% against severe COVID-19 caused by the Omicron sub-lineage BA.1.1.529 variant compared with one-dose booster immunization. The effectiveness of the booster immunization with RNA-based vaccine BNT162b2 or mRNA-1273 was over 75% against severe COVID-19 more than 17 weeks after booster immunization whereas the heterogenous booster immunization showed better effectiveness than homologous booster immunization. In summary, the current COVID-19 vaccines could effectively protect COVID-19 caused by Delta and Omicron variants but was less effective against Omicron variant infection. One-dose booster immunization could enhance protection capability, and two-dose booster immunization could provide additional protection against severe COVID-19.

Effectiveness of COVID-19 Vaccine Booster Shot Compared with Non-Booster: A Meta-Analysis

The analysis of the effectiveness of booster shots compared with primary vaccination is extremely vital. This paper aimed to summarize the results of all available evidence studies on the effectiveness of booster vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Articles published up to 21 June 2022 were systematically searched through PubMed and EMBASE databases. The searched studies were independently assessed for quality using the Newcastle–Ottawa Scale. Results: Seven studies (nine datasets) met the criteria and were included in this study. The pooled results demonstrated a 71% (OR = 0.29, 95% CI = 0.17–0.48) reduction in SARS-CoV-2 infection rates among subjects who received a booster shot compared with those who did not receive a booster shot of coronavirus disease (COVID-19) vaccine. In addition, this analysis emphasized that during the period when the Delta variant was predominant, subjects who received the booster shot showed an 82% (OR = 0.18, 95% CI = 0.13–0.25) reduction in infection rates. Moreover, during the period of dominance of the Omicron variant, subjects who received the booster vaccination displayed a 47% (OR = 0.53, 95% CI = 0.35–0.81) reduction in infection rates. This finding confirmed that booster vaccination against the Omicron variant is significantly less effective than that against the Delta variant. In pandemic periods, correlations between the dominant variant and the efficacy of the COVID-19 vaccine booster should be considered when making vaccine booster plans.

Safety, immunogenicity, and immune persistence of two inactivated COVID-19 vaccines replacement vaccination in China: An observational cohort study

Background

To mitigate a national shortage of WIBP-CorV COVID-19 vaccine, China’s regulator approved administering BBIBP-CorV after WIBP-CorV for completion of a primary series. In a pragmatic observational study, we compared immunogenicity and safety of a primary series of WIBP-CorV followed by BBIBP-CorV with a primary series of two doses of BBIBP-CorV.

Methods

We invited healthy 18–59-years-old adults who had already received either WIBP-CorV or BBIBP-CorV as their first dose in a primary series to participate in this observational cohort study. Subjects who had received WIBP-CorV as their first dose became the observation group; subjects who had received BBIBP-CorV as their first dose became the control group. All participants received BBIBP-CorV as their second dose. We obtained sera 1, 2, and 6 months after second doses for nAb titer measurement by micro-neutralization cytopathic effect assay with SARS-CoV-2 strain HB01, standardized with WHO International Standard for anti-SARS-CoV-2 immunoglobulin. Safety was assessed for the 7 days after administration of second doses.

Results

Between March and December 2021, 275 subjects were included in the observation group and 133 in the control group. Neutralizing seropositivity (≥1:4) rates were 98.91 % and 99.25 % at 1 month and 53.16 % and 70.69 % at 6 months. One-month geometric mean titers (GMTs) were 21.33 and 22.45; one-month geometric mean concentrations (GMCs) were 227.71 IU/mL and 273.27 IU/mL. One to two months after vaccination, observation group seropositivity rates and titers were not significantly different to the control group’s. Adverse reaction rates were 11.27 % and 18.80 %, all mild or moderate in severity.

Conclusions

Both primary series were immunogenic; immunogenicity of WIBP-CorV followed by BBIBP-CorV was not different than immunogenicity following two doses of BBIBP-CorV for two months after vaccination; safety profiles were acceptable for both regimens. BBIBP-CorV can be used to complete a primary series that started with WIBP-CorV.

Microbiota and COVID-19: Long-term and complex influencing factors

The coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). According to the World Health Organization statistics, more than 500 million individuals have been infected and more than 6 million deaths have resulted worldwide. Although COVID-19 mainly affects the respiratory system, considerable evidence shows that the digestive, cardiovascular, nervous, and reproductive systems can all be involved. Angiotensin-converting enzyme 2 (AEC2), the target of SARS-CoV-2 invasion of the host is mainly distributed in the respiratory and gastrointestinal tract. Studies found that microbiota contributes to the onset and progression of many diseases, including COVID-19. Here, we firstly conclude the characterization of respiratory, gut, and oral microbial dysbiosis, including bacteria, fungi, and viruses. Then we explore the potential mechanisms of microbial involvement in COVID-19. Microbial dysbiosis could influence COVID-19 by complex interactions with SARS-CoV-2 and host immunity. Moreover, microbiota may have an impact on COVID-19 through their metabolites or modulation of ACE2 expression. Subsequently, we generalize the potential of microbiota as diagnostic markers for COVID-19 patients and its possible association with post-acute COVID-19 syndrome (PACS) and relapse after recovery. Finally, we proposed directed microbiota-targeted treatments from the perspective of gut microecology such as probiotics and prebiotics, fecal transplantation and antibiotics, and other interventions such as traditional Chinese medicine, COVID-19 vaccines, and ACE2-based treatments.

Assessment of Heterologous and Homologous Boosting With Inactivated COVID-19 Vaccine at 3 Months Compared With Homologous Boosting of BNT162b2 at 6 Months

IMPORTANCE

Evidence for the timing of booster vaccination after completion of BNT162b2 and CoronaVac primary vaccination is crucial to guide policy recommendations.

OBJECTIVE

To compare the odds of symptomatic SARS-CoV-2 infection and COVID-19-related outcomes after heterologous and homologous boosting of CoronaVac at 3-month intervals and homologous boosting of BNT162b2 at 6-month intervals, with BNT162b2 primary series (2 doses) as the reference group.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study used national data for Malaysia. Participants included all individuals aged 18 years and older who received a complete primary series of CoronaVac or BNT162b2 vaccine and were eligible for a booster dose between November 21, 2021, and December 28, 2021. Data were analyzed from November 21, 2021, to January 7, 2022.

EXPOSURES

Receipt of a booster vs no booster and categorized into primary series BNT162b2 (2 doses of BNT162b2), primary series CoronaVac (2 doses of CoronaVac), 3 doses of BNT162b2, primary series CoronaVac plus a BNT162b2 booster, and 3 doses of CoronaVac.

MAIN OUTCOMES AND MEASURES

The primary outcome was symptomatic SARS-CoV-2 infection. The secondary outcomes were COVID-19-related intensive care unit admission and death. All outcomes were observed from the day an individual was considered fully boosted (≥14 days after booster dose).

RESULTS

Our cohort included 13 840 240 individuals (mean [SD] age, 39.9 [15.5] years; 7 040 298 [50.9%] men; 4 451 180 individuals [32.2%] with ≥1 comorbidities), of whom 5 081 641 individuals (36.7%) had received a booster dose. Using the primary series BNT162b2 recipients as reference, the adjusted odds against symptomatic SAR-CoV-2 infection were lower for individuals who received the primary series CoronaVac plus a BNT162b2 (adjusted odds ratio [aOR], 0.06 [95% CI, 0.05-0.06]), 3 doses of CoronaVac (aOR, 0.08 [95% CI, 0.06-0.10]), or 3 doses of BNT162b2 (aOR, 0.01 [95% CI, 0.00-0.01]). Receipt of heterologous booster (primary series of CoronaVac plus a BNT162b2 booster) was associated with lower odds of SARS-CoV-2 infection (aOR, 0.17 [95% CI, 0.17-0.18]) compared with homologous booster (3 doses of CoronaVac) for individuals aged 60 years and older (aOR, 0.19 [95% CI, 0.19-0.20]).

CONCLUSIONS AND RELEVANCE

In this cohort study, for individuals who received the CoronaVac primary series and a booster dose of BNT162b2 or CoronaVac at 3 months, the observed odds of symptomatic SARS-CoV-2 infection were similar to individuals who received the BNT162b2 primary series plus a third dose of BNT162b2 at 6 months. Heterologous booster is recommended for individuals aged 60 years or older who received the CoronaVac primary series, given the lower observed odds against symptomatic SARS-CoV-2 infection among those who received a BNT1612b2 booster.

Strength and durability of antibody responses to BNT162b2 and CoronaVac

We studied 2780 adults in Hong Kong who received CoronaVac inactivated virus vaccine (Sinovac) and BNT162b2 mRNA vaccine ("Comirnaty", BioNTech/Fosun Pharma). We compared rates of antibody waning over time using an enzyme-linked immunosorbent assay for spike receptor binding domain and a surrogate virus neutralization test. We found stronger and more durable antibody responses to two doses of the mRNA vaccine, and slightly stronger initial antibody responses to each vaccine in younger adults and women. The weaker and less durable responses following CoronaVac support earlier provision of third doses to persons who previously received two doses of this vaccine.

Serial negative response after standard and third (Booster) dose of COVID-19 inactivated vaccine is associated with low vitamin D levels in patients with solid cancers

INTRODUCTION

The response is poorly understood to the third dose in patients with cancer who failed the standard dose of inactivated SARS-CoV-2 vaccines (CoronaVac). We aim to assess the immune response to the third dose and identify whether vitamin D deficiency is associated with serial serologic failure in patients with cancer.

METHODS

Solid cancer patients (SCP-N) and healthy controls (HCs) who were seronegative after the standard-dose vaccines in our previous study were prospectively recruited, from October 2021 to February 2022, to receive the third dose vaccines and anti-SARS-CoV-2S antibodies were measured. SCP-N who failed the third dose (serial seronegative group, SSG) were matched by propensity scores with the historical standard-dose positive cancer patient group (robust response group, RRG). An exploratory analysis was carried out to validate the role of vitamin D on the serology response.

RESULTS

The multi-center study recruited 97 SCP-N with 279 positive controls as RRG and 82 negative controls as HC group. The seroconversion rate after third-dose vaccination was higher in SCP-N than in HC (70.6% vs. 29.4%, p < 0.01). The matched comparison showed that patients in SSG had a significantly lower level of vitamin D and consumption rate than RRG or RRG-B (RRG with third-dose positive) (all p < 0.01). None had serious (over grade II) adverse events after the third dose.

CONCLUSION

Solid cancer patients with second-dose vaccine failure may have a relatively poor humoral response to the third dose of COVID-19 vaccines as compared with the seronegative HC group. The consecutively poor humoral response could be associated with poor vitamin D levels and intake. Vitamin D status and cancer-related immune compromise may jointly affect the humoral response following booster vaccination.

Humoral immune response characterization of heterologous prime-boost vaccination with CoronaVac and BNT162b2

Background

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has proven to be a successful strategy for prevent severe infections. CoronaVac and BNT162b2 are the most used vaccines worldwide, but their use in heterologous vaccination schedules is still subjected to evaluation.

Methods

Fifty healthy individuals who received heterologous prime-boost vaccination with CoronaVac and BNT162b2 were enrolled in a post-vaccination serological follow-up longitudinal prospective study. We evaluated specific serum anti-receptor binding domain (RBD) IgG antibody levels, and their capacity to block RBD-ACE2 interaction with a surrogate neutralization assay. In 20 participants, we assessed antibody binding kinetics by surface plasmon resonance, and Fc-mediated functions by ADCC and ADCP reporter assays.

Results

Our baseline seronegative cohort, displayed seroconversion after two doses of CoronaVac and an important decrease in serum anti-RBD IgG antibodies levels 80 days post-second dose. These levels increased significantly early after the third dose with BNT162b2, but 73 days after the booster we found a new fall. Immunoglobulin functionalities showed a similar behavior.

Conclusions

The heterologous prime-boost vaccination with CoronaVac and BNT162b2 generated an impressive increase in serum anti-RBD specific antibody levels followed by a drop. Nevertheless, these titers remained well above those found in individuals only vaccinated with CoronaVac in the same elapsed time. Serum IgG levels showed high correlation with antibody binding analysis, their capacity to block RBD-ACE2 interaction, and Fc-effectors mechanisms. Our work sheds light on the humoral immune response to heterologous vaccination with CoronaVac and BNT162b2, to define a post-vaccination correlate of protection against SARS-CoV-2 infection and to discuss the scheduling of future vaccine boosters in general population.

Effectiveness and Cost-Effectiveness of Inactivated Vaccine to Address COVID-19 Pandemic in China: Evidence From Randomized Control Trials and Real-World Studies

Objective

This study aimed to determine the efficacy, effectiveness, and cost-effectiveness of inactivated COVID-19 vaccines (CoronaVac and BBIBP-CorV) in China using existing international clinical trials and real-world evidence.

Methods

Through a search of PubMed, Embase, Web of Science, and CNKI, studies investigating the effectiveness of inactivated COVID-19 vaccines were identified, and a meta-analysis was undertaken to synthesize the vaccine efficacy and effectiveness data. Moreover, a decision-analytic model was developed to estimate the cost-effectiveness of inactivated vaccines for combating the COVID-19 pandemic in the Chinese context from a societal perspective. Results of the meta-analysis, along with cost data from official websites and works of literature were used to populate the model. Sensitivity analysis was performed to test the robustness of the model results.

Results

A total of 24 studies were included in the meta-analysis. In comparison to no immunization, the effectiveness of inactivated vaccine against COVID-19 infection, hospitalization, ICU admission and death were 65.18% (95% CI 62.62, 67.75), 79.10% (95% CI 71.69, 86.51), 90.46% (95% CI 89.42, 91.50), and 86.69% (95% CI 85.68, 87.70); and the efficacy against COVID-19 infection and hospitalization were 70.56% (95% CI 57.87, 83.24) and 100% (95% CI 61.72, 100). Inactivated vaccine vaccination prevented more infections, hospitalizations, ICU admissions, and deaths with lower total costs, thus was cost-saving from a societal perspective in China. Base-case analysis results were robust in the one-way sensitivity analysis, and the percentage of ICU admission or death and direct medical cost ranked the top influential factors in our models. In the probabilistic sensitivity analysis, vaccination had a 100% probability of being cost-effective.

Conclusion

Inactivated vaccine is effective in preventing COVID-19 infection, hospitalization, ICU admission and avoiding COVID-19 related death, and COVID-19 vaccination program is cost-saving from societal perspective in China.

Relative Vaccine Effectiveness of the Third Dose of CoronaVac or BNT162b2 Following a Two-Dose CoronaVac Regimen: A Prospective Observational Cohort Study from an Adult Vaccine Center in Turkey

Coronavirus disease 2019 (COVID-19) continues to pose a threat to public health with the potential for the emergence of new variants. Vaccines are the milestones to control and slow down the damage of the pandemic. As of January 2021, a two-dose regimen with CoronaVac was authorized in Turkey. Due to the waning seroprevalence rate of SARS-CoV-2 over time, BNT162b2 or CoronaVac has been administered as the third dose following a two-dose CoronaVac regimen as a national vaccination policy. As of 14 January 2021, 5243 volunteers who received two doses of the CoronaVac vaccine at Hacettepe University Adult Vaccine Center were followed prospectively. In our study, relative vaccine effectiveness (VE^ff) for the third dose of the CoronaVac was 58.24% and 87.27% for BNT162b2 in preventing symptomatic COVID-19 cases. There were no hospitalizations, intensive care unit admissions, or deaths in third-dose booster groups with either BNT162b2 or CoronaVac, yielding 100% effectiveness. Both homologous or heterologous third-dose boosters provided further protection against severe COVID-19 and should be prioritized as an effective strategy to combat the COVID-19 pandemic.

Physical activity and antibody persistence 6 months after the second dose of CoronaVac in immunocompromised patients

This prospective cohort study within an open-label, single-arm, phase 4 vaccination trial (clinicaltrials.gov #NCT04754698) aimed to investigate the association between physical activity and persistent anti-SARS-CoV-2 antibodies 6 months after two-dose schedule of CoronaVac in autoimmune rheumatic diseases (ARD) patients (n = 748). Persistent immunogenicity 6 months after the full-course vaccination was assessed using seroconversion rates of total anti-SARS-CoV-2 S1/S2 IgG, geometric mean titers of anti-S1/S2 IgG (GMT), and frequency of positive neutralizing antibodies (NAb). Physical activity was assessed trough questionnaire. Adjusted point estimates from logistic regression models indicated that physically active patients had greater odds of seroconversion rates (OR: 1.5 [95%CI: 1.1 to 2.1]) and NAb positivity (OR: 1.5 [95%CI: 1.0 to 2.1]), and approximately 43% greater GMT (42.8% [95%CI: 11.9 to 82.2]) than inactive ones. In conclusion, among immunocompromised patients, being physically active was associated with an increment in antibody persistence through 6 months after a full-course of an inactivated SARS-CoV-2 vaccine.

Persistence of immunity and impact of third dose of inactivated COVID-19 vaccine against emerging variants

This is a comprehensive report on immunogenicity of COVAXIN^® booster dose against ancestral and Variants of Concern (VOCs) up to 12 months. It is well known that neutralizing antibodies induced by COVID-19 vaccines wane within 6 months of vaccination leading to questions on the effectiveness of two-dose vaccination against breakthrough infections. Therefore, we assessed the persistence of immunogenicity up to 6 months after a two or three-dose with BBV152 and the safety of a booster dose in an ongoing phase 2, double-blind, randomized controlled trial (ClinicalTrials.gov: NCT04471519). We report persistence of humoral and cell mediated immunity up to 12 months of vaccination, despite decline in the magnitude of antibody titers. Administration of a third dose of BBV152 increased neutralization titers against both homologous (D614G) and heterologous strains (Alpha, Beta, Delta, Delta Plus and Omicron) with a slight increase in B cell memory responses. Thus, seronversion rate remain high in boosted recipients compared to non-booster, even after 6 months, post third dose against variants. No serious adverse events observed, except pain at the injection site, itching and redness. Hence, these results indicate that a booster dose of BBV152 is safe and necessary to ensure persistent immunity to minimize breakthrough infections of COVID-19, due to newly emerging variants.

Trial registration: Registered with the Clinical Trials Registry (India) No. CTRI/2021/04/032942, dated 19/04/2021 and on Clinicaltrials.gov: NCT04471519.

Urban monitoring, evaluation and application of COVID-19 listed vaccine effectiveness: a health code blockchain study

OBJECTIVE

By using health code blockchain, cities can maximise the use of personal information while maximising the protection of personal privacy in the monitoring and evaluation of the effectiveness of listed vaccines.

DESIGN

This study constructs an urban COVID-19 listed vaccine effectiveness (VE) monitoring, evaluation and application system based on the health code blockchain. This study uses this system and statistical simulation to analyse three urban application scenarios, namely evaluating the vaccination rate (VR) and determining the optimal vaccination strategy, evaluating herd immunity and monitoring the VE on variant.

MAIN OUTCOME MEASURES

The primary outcomes first establish an urban COVID-19 listed VE monitoring, evaluation and application system by using the health code blockchain, combined with the dynamic monitoring model of VE, the evaluation index system of VE and the monitoring and evaluation system of personal privacy information use, and then three measures are analysed in urban simulation: one is to take the index reflecting urban population mobility as the weight to calculate the comprehensive VR, the second is to calculate the comprehensive basic reproduction number (R) in the presence of asymptomatic persons, the third is to compare the difference between the observed effectiveness and the true effectiveness of listed vaccines under virus variation.

RESULTS

Combining this system and simulation, this study finds: (1) The comprehensive VR, which is weighted to reflect urban population mobility, is more accurate than the simple VR which does not take into account urban population mobility. Based on population mobility, the algorithm principle of urban optimal vaccination strategy is given. In the simulation of urban listed vaccination involving six regions, programmes 1 and 5 have the best protective effect among the eight vaccination programmes, and the optimal vaccination order is 3-5-2-4-6-1. (2) In the presence of asymptomatic conditions, the basic reproduction number, namely R0*(1-VR*VE), does not accurately reflect the effect of herd immunity, but the comprehensive basic reproduction number (R) should be used. The R is directly proportional to the proportion of asymptomatic people (aw) and the duration of the incubation period (ip), and inversely proportional to the VR, the VE and the number of days transmitted in the ip (k). In the simulation analysis, when symptomatic R0=3, even with aw=0.2, the R decreases to nearly 1 until the VR reaches 95%. When aw=0.8, even when the entire population is vaccinated, namely VR=1, the R is 1.688, and still significantly greater than 1. If the R is to be reduced to 1, the VE needs to be increased to 0.87. (3) This system can more comprehensively and accurately grasp the impact of the variant virus on urban VE. The traditional epidemiological investigation can lose the contacts of infected persons, which leads to the deviation between the observed effectiveness and the true effectiveness. Virus variation aggravates the loss, and then increases the deviation. Simulation case 1 assumes the unvaccinated rate of 0.8, the ongoing VR of 0.1, the completed VR of 0.1 and an average infection rate of 2% for the variant virus. If a vaccine is more than 90% effectiveness against the premutant virus, but only 80% effectiveness against the mutant virus, and because 80% of the unvaccinated people who are not infected are not observed, the observed effectiveness of the vaccine is 91.76%, it will lead to the wrong judgement that the VE against the variant virus is not decreased. Simulation case 2 assumes the unvaccinated rate of 0.8, the ongoing VR of 0.1, the completed VR of 0.1 and an average infection rate of 5% for the variant virus. Simulation finds that the higher the proportion of unvaccinated infected people who are not observed, the lower the estimate of observed effectiveness; and the lower the true effectiveness, the larger the gap between observed effectiveness and true effectiveness. Simulation case 3 assumes the unvaccinated rate of 0.2, the ongoing VR of 0.2, the completed VR of 0.6 and an average infection rate of 2% for the variant virus. Simulation finds that the higher the proportion of unobserved completed vaccination patients who are not infected, the lower the estimate of observed effectiveness; and the lower the true effectiveness, the larger the gap between observed effectiveness and true effectiveness. Simulation case 4 assumes the unvaccinated rate of 0.2, the ongoing VR of 0.2, the completed VR of 0.6 and an average infection rate of 5% for the variant virus. If a vaccine is more than 90% effectiveness against the premutant virus, but only 80% effectiveness against the mutant virus, and because 80% of the infected people with complete vaccination are not observed, the observed effectiveness of the vaccine is 91.95%, similar to case 1, it will lead to the wrong judgement that the VE against the variant virus is not decreased.

CONCLUSION

Compared with traditional epidemiological investigation, this system can meet the challenges of accelerating virus variation and a large number of asymptomatic people, dynamically monitor and accurately evaluate the effectiveness of listed vaccines and maximise personal privacy without locking down the relevant area or city. This system established in this study could serve as a universal template for monitoring and evaluating the effectiveness of COVID-19 listed vaccines in cities around the world. If this system can be promoted globally, it will promote countries to strengthen unity and cooperation and enhance the global ability to respond to COVID-19.

Assessment of neutralizing antibody responses after natural SARS-CoV-2 infection and vaccination in congolese individuals

Background

Assessing immune responses after vaccination is part of the evaluation package of vaccine effectiveness in the real world. Regarding SARS-CoV-2, neutralizing antibody levels has been shown to be a good indicator of antibody immune response boosting. So far, limited data have been reported from Africa including in Central Africa. The objective of this study was to provide data on anti-S1 spike total IgG and neutralizing antibodies in vaccinated and non-vaccinated including naturally infected Congolese population during B.1.214.1 and B.1.617.2 variant waves.

Methods

Recruited patients were divided into 4 groups: (1) Naturally infected by the B.1.214.1 variant on January 2021 and followed up until September 2021. These patients have been vaccinated at month 07 and then followed up for 2 months post vaccination; (2) Naturally infected by the B.1.617.2 variant from June 2021; (3) unvaccinated SARS-CoV-2 individuals with no history of prior SARS-CoV-2 infection; (4) fully vaccinated individuals with sinopharm/BBIP-CorV or Janssen/Ad26.COV2.S. SARS-CoV-2 was detected by qRT-PCR and sequenced using Next-Generation Sequencing. ELISA method was used for detecting IgG, and neutralizing Antibody against SARS-CoV-2 antigens using commercial neutralizing assay.

Results

Individuals infected by the B.1214.1 variant elicited consistently high IgG titers at 02, 03 and 06 months. Two months post vaccination with BBIP-CorV, participants showed a significant increase by × 2.5 fold (p < 0.0001) of total IgG and X1.5 fold for neutralizing antibody capacity. This study showed that natural infection with B1.617.2 (delta) variant was more immunogenic compared to those being infected with B1.214.2 variant.

We found a significantly higher concentration in anti-SARS-CoV-2 IgG (p < 0.0002) and antibodies neutralization capacity (P < 0.0001) in fully vaccinated compared to unvaccinated participants. Two months post vaccination, individuals who received Janssen/Ad26.COV2.S presented higher (p = 0.01) total IgG to spike protein compared to BBIP-CorV.

Conclusion

Both natural infection and vaccination with BBIP-CorV and Janssen/Ad26.COV2.S induced antibody response in Congolese population. In addition, Janssen/Ad26.COV2.S was more immunogenic than Sinopharm/BBIP-CorV. There is a need to investigate the duration of these antibodies both in previously infected and naive vaccinated Congolese to allow public heath stakeholders to make evidence-based decision on vaccine schedule for the Congolese population.

Will People Accept a Third Booster Dose of the COVID-19 Vaccine? A Cross-Sectional Study in China

Objective

The coronavirus disease 2019 (COVID-19) vaccines are considered to be an effective way to prevent the spread of the infection. Our previous study has shown that about 75% of healthcare workers (HCWs) in China were willing to receive the vaccine when it became available. Here, we examined the acceptance of a third booster dose among Chinese people and identified the influencing factors.

Methods

A cross-sectional online survey was conducted and the snowball sampling method was utilized. An online questionnaire was provided to all the participants in the form of a quick response (QR) code. The questionnaire included general demographic information, views on vaccines, the General Health Questionnaire-12 (GHQ-12), and the Depression, Anxiety, and Stress Scale-21 (DASS-21). The univariate analysis was done between all the variables and our dependent variable. Then, we used the multivariate logistic regression model to examine the influencing factors of the third booster dose acceptance.

Results

We collected 1,062 complete answers. Of these, 90.39% (n = 960) declared that they would accept the booster dose. Knowing more about the vaccine and recognizing the efficacy of vaccines were significantly associated with greater acceptance of the booster dose. People willing to take the booster dose had better psychological health. A belief that the booster dose could prevent severe infection caused by COVID-19 and enhance the effectiveness of the first two doses were the main contributing factors to vaccine acceptance. Vaccine hesitancy was mainly due to a low perceived risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and rapid mutation of SARS-CoV-2.

Conclusion

This study revealed that Chinese people were very receptive to the third booster dose, which is an inspiring result. More positive attitudes regarding COVID-19 vaccination were supported by its efficacy and few side effects.

Immunity after COVID-19 Recovery and Vaccination: Similarities and Differences

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is associated with a robust immune response. The development of systemic inflammation leads to a hyperinflammatory state due to cytokine release syndrome during severe COVID-19. The emergence of many new SARS-CoV-2 variants across the world deteriorates the protective antiviral immunity induced after infection or vaccination. The innate immune response to SARS-CoV-2 is crucial for determining the fate of COVID-19 symptomatology. T cell-mediated immunity is the main factor of the antiviral immune response; moreover, SARS-CoV-2 infection initiates a rapid B-cell response. In this paper, we present the current state of knowledge on immunity after COVID-19 infection and vaccination. We discuss the mechanisms of immune response to various types of vaccines (nucleoside-modified, adenovirus-vectored, inactivated virus vaccines and recombinant protein adjuvanted formulations). This includes specific aspects of vaccination in selected patient populations with altered immune activity (the elderly, children, pregnant women, solid organ transplant recipients, patients with systemic rheumatic diseases or malignancies). We also present diagnostic and research tools available to study the anti-SARS-CoV-2 cellular and humoral immune responses.

Immunogenicity, efficacy and safety of COVID-19 vaccines: an update of data published by 31 December 2021

The unprecedented coronavirus disease 2019 (COVID-19) pandemic has caused a disaster for public health in the last 2 years, without any sign of an ending. Various vaccines were developed rapidly as soon as the outbreak occurred. Clinical trials demonstrated the reactogenicity, immunogenicity and protection efficacy in humans, and some of the vaccines have been approved for clinical use. However, waves of infections such as the recently circulating Omicron variant still occur. Newly emerging variants, especially the variants of concern, and waning humoral responses pose serious challenges to the control of the COVID-19 pandemic. Previously, we summarized the humoral and cellular immunity, safety profiles and protection efficacy of COVID-19 vaccines with clinical data published by 21 May 2021. In this review, we summarize and update the published clinical data of COVID-19 vaccines and candidates up to 31 December 2021.

Immune Persistence and Safety After SARS-CoV-2 BNT162b1 mRNA Vaccination in Chinese Adults: A Randomized, Placebo-Controlled, Double-Blind Phase 1 Trial

Introduction

BNT162b1 is a lipid nanoparticle-formulated, nucleoside-modified mRNA SARS-CoV-2 vaccine. Here, we report safety and immune persistence data following a primary two-dose vaccination schedule administered 21 days apart.

Methods

Immune persistence was determined at month 3 in 72 younger participants (aged 18–55 years) and at month 6 in 70 younger and 69 older participants (aged 65–85 years).

Results

In younger participants, neutralizing antibody (nAb) geometric mean titers (GMTs) for the 10 and 30 µg dose levels declined from 233 and 254 (21 days after dose 2) to 55 and 87 at month 3, respectively, and to 16 and 27 at month 6, respectively. In older participants, nAb GMTs declined from 80 and 160 (21 days after dose 2) to 10 and 21 at month 6. Overall, higher antibody titers were observed in younger participants, and the 30 µg dose induced higher levels of nAb, which declined more slowly by month 6. No serious adverse events were reported in the vaccine group.

Conclusion

This study showed BNT162b1 maintains a favorable safety profile in younger and older participants in the 6 months after vaccination. This study further extends our understanding of immune persistence and the safety of the BNT162b1 vaccine as a candidate vaccine in the BioNTech pipeline.

Trial Registration Number

NCT04523571, registered August 21, 2020.

Protocol of an Exploratory Single-Arm Study to Evaluate the Safety and Immunogenicity of KD-414 as a Booster Vaccine for SARS-CoV-2 in Healthy Adults (KAPIVARA)

Background: The coronavirus disease 2019 (COVID-19) pandemic is currently ongoing, and there have been significant efforts in the development of COVID-19 vaccines. However, the neutralizing antibody titers in vaccinated individuals are reported to progressively decrease over time. Japanese pharmaceutical companies have published the results of Phase I and II studies on the safety and efficacy of different vaccines. Final clinical trials will be conducted with the aim of practical application by March 2023. To effectively utilize vaccines developed by Japanese companies, the efficacy and safety of a booster dose (i.e., third vaccination) must be evaluated among individuals who have received three doses of different vaccines. Methods: This protocol describes a study that aims to examine the effect of a booster dose of “KD-414”, a novel Japanese inactivated vaccine, on antibody titers among participants involved in a previous study. Volunteers in this protocol will be recruited from participants in the previous study and immunized with KD-414 after obtaining consent. The antibody titers, before and after immunization with KD-414, among participants who previously received two doses of the BNT162b2 mRNA vaccine, will be comparatively analyzed. Discussion: The reactogenicity and immunogenicity of seven different COVID-19 vaccines including an inactivated vaccine as a third dose after two doses of ChAdOx1 nCov-19 or BNT162b2, has been tested previously, and found to be superior to control (quadrivalent meningococcal conjugate vaccine) regardless of which vaccine had been received during the initial course. This suggests that many types of third booster doses are efficacious. It is anticipated that this study will provide evidence of the safety and immunogenicity of KD-414 as a booster vaccine, which will have profound public health implications.

The kinetics of IgG subclasses and contributions to neutralizing activity against SARS-CoV-2 wild-type strain and variants in healthy adults immunized with inactivated vaccine

Neutralizing antibody is an important indicator of vaccine efficacy, of which IgG is the main component. IgG can be divided into four subclasses. Up to now, studies analysing the humoral response to SARS‐CoV‐2 vaccination have mostly focused on measuring total IgG, and the contribution of specific IgG subclasses remains elusive. The aim of this study is to investigate the kinetics of neutralizing antibodies and IgG subclasses, and to explore their relationships in people vaccinated with inactivated COVID‐19 vaccine. We conducted a prospective cohort study in 174 healthy adults aged 18–59 years old who were administrated 2 doses of CoronaVac 14 days apart and a booster dose 1 year after the primary immunization, and followed up for 15 months. Blood samples were collected at various time points after primary and booster immunization. We used live SARS‐CoV‐2 virus neutralizing assay to determine neutralizing ability against the wild‐type strain and 4 variants (Beta, Gamma, Delta and Omicron) and ELISA to quantify SARS‐CoV‐2 RBD‐specific IgG subclasses. The results showed that the 2‐dose primary immunization only achieved low neutralizing ability, while a booster shot can significantly enhance neutralizing ability against the wild‐type strain, Beta, Gamma, Delta and Omicron variants. IgG1 and IgG3 were the most abundant serum antibodies, and IgG2 and IgG4 were hardly detected at any time. The ratio of IgG1/IgG3 was positively associated with the neutralization ability. The underlying mechanism requires further exploration.

Evaluation of Immunogenicity and Safety of Vero Cell-Derived Inactivated COVID-19 Vaccine in Older Patients with Hypertension and Diabetes Mellitus

Background: To evaluate the immunogenicity and safety of the COVID-19 vaccine (Vero cell), inactivated, in a population aged ≥60 years with hypertension or(/and) diabetes mellitus. Methods: A total of 1440 participants were enrolled and divided into four groups, 330 in the hypertension group, 330 in the diabetes group, 300 in the hypertensive combined with diabetes group (combined disease group), and 480 in the healthy population group. Two doses of the COVID-19 vaccine (Vero cell), inactivated, were administered at a 21-day interval and blood samples were collected before vaccination and 28 days after the second dose to evaluate the immunogenicity. The adverse events and changes in blood pressure and blood glucose levels after vaccination were recorded. Results: The seroconversion rate of the COVID-19 neutralizing antibodies was 100% for all participants. The post-inoculation geometric mean titer (GMT) in the four groups of the hypertension, diabetes, combined disease, and healthy populations were 73.41, 69.93, 73.84, and 74.86, respectively. The seroconversion rates and post-vaccination GMT in the hypertension, diabetes, and combined disease groups were non-inferior to the healthy population group. The rates of vaccine-related adverse reactions were 11.93%, 14.29%, 12.50%, and 9.38%, respectively. No serious adverse events were reported during the study. No apparent abnormal fluctuations in blood pressure and blood glucose values were observed after vaccination in participants with hypertension or(/and) diabetes. Conclusions: The COVID-19 vaccine (Vero cell), inactivated, showed good immunogenicity and safety in patients aged ≥60 years suffering from hypertension or(/and) diabetes mellitus.

An intranasally administrated SARS-CoV-2 beta variant subunit booster vaccine prevents beta variant replication in rhesus macaques

Emergence of SARS-CoV-2 variants and waning of vaccine/infection-induced immunity pose threats to curbing the COVID-19 pandemic. Effective, safe, and convenient booster vaccines are in need. We hypothesized that a variant-modified mucosal booster vaccine might induce local immunity to prevent SARS-CoV-2 infection at the port of entry. The beta-variant is one of the hardest to cross-neutralize. Herein, we assessed the protective efficacy of an intranasal booster composed of beta variant-spike protein S1 with IL-15 and TLR agonists in previously immunized macaques. The macaques were first vaccinated with Wuhan strain S1 with the same adjuvant. A total of 1 year later, negligibly detectable SARS-CoV-2-specific antibody remained. Nevertheless, the booster induced vigorous humoral immunity including serum- and bronchoalveolar lavage (BAL)-IgG, secretory nasal- and BAL-IgA, and neutralizing antibody against the original strain and/or beta variant. Beta-variant S1-specific CD4⁺ and CD8⁺ T cell responses were also elicited in PBMC and BAL. Following SARS-CoV-2 beta variant challenge, the vaccinated group demonstrated significant protection against viral replication in the upper and lower respiratory tracts, with almost full protection in the nasal cavity. The fact that one intranasal beta-variant booster administrated 1 year after the first vaccination provoked protective immunity against beta variant infections may inform future SARS-CoV-2 booster design and administration timing.

Booster Doses of Anti COVID-19 Vaccines: An Overview of Implementation Policies among OECD and EU Countries

The need for an anti-COVID-19 booster dose posed an organizational challenge for health policy makers worldwide. Therefore, this study aimed to explore the health policies regarding the booster dose through an overview of recommendations issued in high-income countries. Between 10 November and 16 December 2021, the authors searched for state-level official documents about the offer of the booster dose, considering the 43 countries belonging to the European Union (EU) or the Organisation for Economic Co-operation and Development (OECD). Mainly due to the lack of English translation, 15 countries were excluded. A total of 135 documents were selected. Almost all the countries started administering the booster dose between September and November 2021. The most used products were mRNA vaccines, followed by Vaxzevria-AstraZeneca and Jcovden-Janssen/Johnson & Johnson. All countries established criteria to define categories of individuals to be vaccinated as a priority. A six/five-months interval was the main choice for general population vaccinated with mRNA vaccines, while shorter intervals were chosen for vulnerable individuals or other vaccines. Despite diversities related to the differences in health systems, economical resources, and population numbers, and the need to adapt all these factors to a massive vaccination campaign, a progressive convergence towards the same vaccination policies was highlighted.

Efficacy of heterologous boosting against SARS-CoV-2 using a recombinant interferon-armed fusion protein vaccine (V-01): a randomized, double-blind and placebo-controlled phase III trial

Waning of neutralizing titres along with decline of protection efficacy after the second dose of COVID-19 vaccines was observed, including China-made inactivated vaccines. Efficacy of a heterologous boosting using one dose of a recombinant SARS-CoV-2 fusion protein vaccine (V-01) in inactivated vaccine-primed population was studied, aimed to restore the immunity. A randomized, double-blind and placebo-controlled phase III trial was conducted in healthy people aged 18 years or older in Pakistan and Malaysia. Each eligible participant received one dose of the V-01 vaccine developed by Livzon Mabpharm Inc. or placebo within the 3-6 months after the two-dose primary regimen, and was monitored for safety and efficacy. The primary endpoint was protection against confirmed symptomatic SARS-CoV-2 infection. A total of 10,218 participants were randomly assigned to receive a vaccine or placebo. Virus-neutralizing antibodies were assessed in 419 participants. A dramatic increase (11.3-fold; 128.3–1452.8) of neutralizing titres was measured in the V-01 group at 14 days after the booster. Over two months of surveillance, vaccine efficacy was 47.8% (95%CI: 22.6–64.7) according to the intention-to-treat principle. The most common adverse events were transient, mild-to-moderate pain at the injection site, fever, headache, and fatigue. Serious adverse events occurred almost equally in V-01 (0.12%) and placebo (0.16%) groups. The heterologous boosting with the V-01 vaccine was safe and efficacious, which could elicit robust humoral immunity under the epidemic of the Omicron variant.

Trial registration:ClinicalTrials.gov identifier: NCT05096832.

Serological study of CoronaVac vaccine and booster doses in Chile: immunogenicity and persistence of anti-SARS-CoV-2 spike antibodies

BACKGROUND

Chile was severely affected by COVID19 outbreaks but was also one of the first countries to start a nationwide program to vaccinate against the disease. Furthermore, Chile became one of the fastest countries to inoculate a high percentage of the target population and implemented homologous and heterologous booster schemes in late 2021 to prevent potential immunological waning. The aim of this study is to compare the immunogenicity and time course of the humoral response elicited by the CoronaVac vaccine in combination with homologous versus heterologous boosters.

METHODS

We compared the immunogenicity of two doses of CoronaVac and BNT162b2 vaccines and one homologous or heterologous booster through an ELISA assay directed against the ancestral spike protein of SARS-CoV-2. Sera were collected from individuals during the vaccination schedule and throughout the implementation of homologous and heterologous booster programs in Chile.

RESULTS

Our findings demonstrate that a two-dose vaccination scheme with CoronaVac induces lower levels of anti-SARS-CoV-2 spike antibodies than BNT162b2 in a broad age range (median age 42 years; interquartile range (IQR) 27-61). Furthermore, antibody production declines with time in individuals vaccinated with CoronaVac and less noticeably, with BNT162b2. Analysis of booster schemes revealed that individuals vaccinated with two doses of CoronaVac generate immunological memory against the SARS-CoV-2 ancestral strain, which can be re-activated with homologous or heterologous (BNT162b2 and ChAdOx1) boosters. Nevertheless, the magnitude of the antibody response with the heterologous booster regime was considerably higher (induction fold BNT162b2: 11.2x; ChAdoX1; 12.4x; CoronaVac: 6.0x) than the responses induced by the homologous scheme. Both homologous and heterologous boosters induced persistent humoral responses (median 122 days, IQR (108-133)), although heterologous boosters remained superior in activating a humoral response after 100 days.

CONCLUSIONS

Two doses of CoronaVac induces antibody titers against the SARS-CoV-2 ancestral strain which are lower in magnitude than those induced by the BNT162b2 vaccine. However, the response induced by CoronaVac can be greatly potentiated with a heterologous booster scheme with BNT162b2 or ChAdOx1 vaccines. Furthermore, the heterologous and homologous booster regimes induce a durable antibody response which does not show signs of decay 3 months after the booster dose.

Immunogenicity of a Third Dose of BNT162b2 to Ancestral Severe Acute Respiratory Syndrome Coronavirus 2 and the Omicron Variant in Adults Who Received 2 Doses of Inactivated Vaccine

BACKGROUND

Limited data exist on antibody responses to mixed vaccination strategies that involve inactivated coronavirus disease 2019 (COVID-19) vaccines, particularly in the context of emerging variants.

METHODS

We conducted an open-label trial of a third vaccine dose of a messenger RNA (mRNA) vaccine (BNT162b2, Fosun Pharma/BioNTech) in adults aged ≥30 years who had previously received 2 doses of inactivated COVID-19 vaccine. We collected blood samples before administering the third dose and 28 days later and tested for antibodies to the ancestral virus using a binding assay (enzyme-linked immunosorbent assay [ELISA]), a surrogate virus neutralization test (sVNT), and a live virus plaque reduction neutralization test (PRNT). We also tested for antibodies against the Omicron variant using live-virus PRNT.

RESULTS

In 315 participants, a third dose of BNT162b2 substantially increased antibody titers on each assay. Mean ELISA levels increased from an optical density of 0.3 to 2.2 (P < .001), and mean sVNT levels increased from an inhibition of 17% to 96% (P < .001). In a random subset of 20 participants, the geometric mean PRNT50 titers rose substantially, by 45-fold from day 0 to day 28 against the ancestral virus (P < .001) and by 11-fold against the Omicron variant (P < .001). In daily monitoring, post-vaccination reactions subsided within 7 days for more than 99% of participants.

CONCLUSIONS

A third dose of COVID-19 vaccine with an mRNA vaccine substantially improved antibody levels against the ancestral virus and the Omicron variant with a well-tolerated safety profile in adults who had received 2 doses of inactivated vaccine 6 months earlier.

CLINICAL TRIALS REGISTRATION

NCT05057182.

Six-month follow-up of a booster dose of CoronaVac in two single-centre phase 2 clinical trials

Determining the duration of immunity induced by booster doses of CoronaVac is crucial for informing recommendations for booster regimens and adjusting immunization strategies. In two single-centre, double-blind, randomised, placebo-controlled phase 2 clinical trials, immunogenicity and safety of four immunization regimens are assessed in adults aged 18 to 59 years and one immunization regimen in adults aged 60 years and older, respectively. Serious adverse events occurring within 6 months after booster doses are recorded as pre-specified secondary endpoints, geometric mean titres (GMTs) of neutralising antibodies one year after the 3-dose schedule immunization and 6 months after the booster doses are assessed as pre-specified exploratory endpoints, GMT fold-decreases in neutralization titres are assessed as post-hoc analyses. Neutralising antibody titres decline approximately 4-fold and 2.5-fold from day 28 to day 180 after third doses in adults aged 18-59 years of age and in adults aged 60 years and older, respectively. No safety concerns are identified during the follow-up period. There are increases in the magnitude and duration of humoral response with homologous booster doses of CoronaVac given 8 months after a primary two-dose immunization series, which could prolong protection and contribute to building our wall of population immunity. Trial number: NCT04352608 and NCT04383574.

A single-center COVID-19 vaccine experience with CoronaVac and BNT162b2 in familial Mediterranean fever patients

Aim

To determine frequency of adverse events and attacks related to vaccination in recipients of CoronaVac and BNT162b2 in familial Mediterranean fever (FMF) patients, and to search whether history of prior COVID‐19 or a booster dose increases occurrence of adverse events/attacks.

Methods

FMF patients were surveyed for administration of any COVID‐19 vaccine and vaccine‐related adverse events or FMF attacks. Demographic, clinical, vaccine‐related data, history of COVID‐19 infection before or after vaccination, adherence to FMF treatment during vaccination were collected.

Results

A total of 161 vaccinated FMF patients were included. Ninety‐three patients out of 161 had reported suffering from an adverse event/attack after a vaccine dose. There were 54.7% of BNT162b2 recipients who reported any adverse event after any vaccine dose in comparison to 29.9% of CoronaVac recipients (P < .001). There were 22.2% of BNT162b2 recipients who reported suffering from a FMF attack within 1 month after vaccination in comparison to 19.4% of CoronaVac recipients (P = .653). When patients with or without adverse event/attack were compared, no significant differences were observed in means of demographics, comorbid diseases, disease duration, total vaccine doses, or treatments adhered to for FMF. Rates of adverse events/attacks were similar between patients with and without prior COVID‐19. In booster recipients, adverse events/attacks were most frequent after the booster dose.

Conclusions

A considerable number of FMF patients suffered from vaccine‐related adverse events/attacks, particularly with BNT162b2. No serious events or mortalities due to vaccination were detected. Demographics, clinical characteristics and prior history of vaccination did not significantly affect these results. We observed an increased rate of adverse events/attacks with booster dose administration.

Multiple sclerosis in the era of COVID-19: disease course, DMTs and SARS-CoV2 vaccinations

PURPOSE OF REVIEW

As of January 21st 2022, over 340 million are confirmed cases of coronavirus disease 2019 (COVID-19), including nearly 5.6 million deaths. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is neurotropic and affects the neural parenchyma through direct viral invasion from the nasal mucosa and postinfectious cytokine storm. Further challenges of SARS-CoV-2 infection are nowadays linked to variants of concern. Multiple sclerosis is an inflammatory and progressive degenerative disorder of the central nervous system commonly affecting young adults and potentially generating irreversible disability. Since the beginning of the SARS-CoV-2 pandemic, people with multiple sclerosis (pwMS) have been considered 'extra' vulnerable because of the immune-mediated nature of the disease, the disability status, and the immunomodulatory therapies potentially increasing the risk for viral infection. Today multiple sclerosis neurologists are faced with several challenges in the management of pwMS to both prevent SARS-CoV-2 infection and protection from disease worsening. We aimed to highlight today's most relevant facts about the complex management of pwMS in the COVID-19 era.

RECENT FINDINGS

The incidence of COVID-19 among pwMS does not differ from the general population. The prognosis of COVID-19 among pwMS is driven by older age, male sex, nonambulatory status, comorbidity as in the general population, as well as by corticosteroid treatment and B-cell depleting agents which decrease seropositivity from SARS-CoV-2 infection and immune responses to SARS-CoV-2 vaccination.

SUMMARY

Disease modifying treatments (DMTs) should be regularly continued in relation to SARS-CoV-2 vaccination, but an ad hoc timing is required with B-cell depleting agents. SARS-CoV-2 vaccination is recommended in pwMS with willingness improving through health education programs. Multiple sclerosis does not seem to worsen after SARS-Cov2 vaccination but COVID-19 may enhance disease activity.

IgG Antibody Responses and Immune Persistence of Two Doses of BBIBP-CorV Vaccine or CoronaVac Vaccine in People Living with HIV (PLWH) in Shenzhen, China

The purpose of this study was to preliminarily evaluate the immunogenicity and immune persistence of inactivated SARS-CoV-2 vaccines in PLWH in the real world. We collected blood samples from 132 PLWH aged 18−59 years who were vaccinated with two doses of BBIBP-CorV vaccine (Sinopharm) or CoronaVac vaccine (SinoVac) at 28 ± 7 days and 180 ± 20 days the after second dose, to detect the level of Spike receptor binding domain-protein specific IgG (S-RBD-IgG) by using chemiluminescence. We found that the BBIBP-CorV vaccine or the CoronaVac vaccine induced lower S-RBD-IgG antibody seropositivity rates and levels in PLWH than in healthy controls (HCs). The BBIBP-CorV vaccine or the CoronaVac vaccine induced lower humoral immune responses in PLWH, having lower CD4+T cell counts (<350 cells/μL) compared to PLWH, and having higher CD4+T cell counts (≥350 cells/μL) after a second dose of vaccination. The BBIBP-CorV vaccine or the CoronaVac vaccine induced lower S-RBD-IgG antibody levels in PLWH, having CD4+T cell counts ≥350 cells/μL compared to HCs. No negative effects were observed in terms of the CD4+T cell counts and HIV RNA viral load (VL) of PLWH after vaccination. Ninety-nine PLWH and eighty-three HCs completed a second blood collection for testing; we found a statistically significant decrease in the humoral immune response both in PLWH and HCs from 28 days to 180 days after a second dose of BBIBP-CorV vaccine or CoronaVac vaccine. The S-RBD-IgG antibody induced by the BBIBP-CorV vaccine or the CoronaVac vaccine declined faster in the PLWH population than in the healthy population, and two doses of the BBIBP-CorV vaccine or the CoronaVac vaccine may not be enough to provide PLWH with persistent immunity against SARS-CoV-2. It is necessary for PLWH to be prioritized for a third dose over the healthy population, but the immunogenicity of the third dose of the homologous or heterologous vaccine requires further study.