ARTICLE | doi:10.20944/preprints202208.0151.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: BNT162b2 mRNA COVID-19 vaccine; COVID-19 vaccine; cardiovascular effects; myocarditis; adolescents; Thailand
Online: 8 August 2022 (10:40:23 CEST)
This study focuses on cardiovascular effects, particularly myocarditis and pericarditis events, after BNT162b2 mRNA COVID-19 vaccine injection in Thai adolescents. This prospective cohort study enrolled students from two schools aged 13–18 years who received the second dose of the BNT162b2 mRNA COVID-19 vaccine. Data including demographics, symptoms, vital signs, ECG, echocardiography and cardiac enzymes were collected at baseline, Day 3, Day 7, and Day 14 (optional) using case record forms.We enrolled 314 participants; of these, 13 participants were lost to follow up, leaving 301 participants for analysis. The most common cardiovascular effects were tachycardia (7.64%), shortness of breath (6.64%), palpitation (4.32%), chest pain (4.32%), and hypertension (3.99%). Seven participants (2.33%) exhibited at least one elevated cardiac biomarker or positive lab assessments. Cardiovascular effects were found in 29.24% of patients, ranging from tachycardia, palpitation, and myopericarditis. Myopericarditis was confirmed in one patient after vaccination. Two patients had suspected pericarditis and four patients had suspected subclinical myocarditis. Conclusion: Cardiovascular effects in adolescents after BNT162b2 mRNA COVID-19 vaccination included tachycardia, palpitation, and myocarditis. The clinical presentation of myopericarditis after vaccination was usually mild, with all cases fully recovering within 14 days. Hence, adolescents receiving mRNA vaccines should be monitored for side effects. Clinical Trial Registration: NCT05288231
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: COVID-19; lymphoma; BNT162b2; mRNA-1273
Online: 28 July 2021 (17:21:17 CEST)
Currently available COVID-19 mRNA vaccines have demonstrated high efficacy in clinical trials.1-3 However, cancer patients, including those with hematological malignancies, were largely excluded from these trials. In this prospective, observational study we measured anti-S protein IgG titers as well as avidity in lymphoma patients (n=67) vaccinated with a COVID-19 mRNA vaccine. Serological response rates in lymphoma patients who were treatment naïve (100% in CLL, 88.9% in other, non-CLL non-Hodgkin lymphoma patients), or who were last treated more than 24 months prior to vaccination (100% in CLL, 90% in other-NHL), were similar to healthy controls (100%). Patients on active therapy, however, had a diminished response rate (40% in CLL, 21.0% in other-NHL). No patient who received anti-CD20 monoclonal antibodies (mAb) within six months of vaccination responded. Thus, the utility of testing anti-S titers should be explored in patients on active therapy or with recent anti-CD20 mAb exposure, to assess their response to vaccination. We also propose studying passive protection with S-protein mAbs as an alternative prophylactic strategy for patients who respond poorly to vaccination.
ARTICLE | doi:10.20944/preprints202308.1465.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: Adolescent; children; 12-17 years COVID-19 vaccine; fully vaccinated; partially vaccinated; vaccination status; RT-PCR-positive; Pfizer; BNT162b2; vaccine effectiveness
Online: 22 August 2023 (03:02:19 CEST)
Qatar experienced five SARS-CoV-2 waves dominated sequentially by the original virus, Alpha, Beta, Omicron BA.1 and BA.2, and Omicron BA.4 and BA.5, in addition to a prolonged low-incidence phase dominated by the Delta variant. The two-dose primary series of BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine against SARS-CoV-2 infection has been approved for use in 10µg formulations among children and adolescents aged 12-17 years as of May 16, 2021. This study aimed at estimating the effectiveness of the 30µg BNT162b2 Pfizer-BioNTech mRNA COVID-19 vaccine against the pre-Omicron variants of SARS-CoV-2 infection in children and adolescents aged 12-17 years residing in Qatar. A test-negative matched case-control study was conducted where any child or adolescent aged 12-17 years who had been tested for SARS-CoV-2, RT-PCR tests performed on nasopharyngeal or oropharyngeal swabs, as part of contact tracing, between June and November 2021 and eligible to receive the BNT162b2 vaccine as per the national guidelines. Data regarding 14,161 children/adolescents meeting inclusion-exclusion criteria were retrieved from the national Surveillance and Vaccine Electronic System (SAVES). Of the total, 3.1% (444) were positive for SARSCoV-2. More than half (55.96%) were vaccinated with two doses of Pfizer-BioNTech-mRNA COVID-19 vaccine. Amongst those immunized with two doses, 1.2% tested positive for SARS CoV2, while 5.6% amongst the unvaccinated tested positive. The vaccine effectiveness was calculated to be 79%. Pfizer-BioNTech mRNA COVID-19 vaccine provides protection from COVID-19 infection for children/adolescents, hence it is crucial to ensure they receive the recommended vaccines.
ARTICLE | doi:10.20944/preprints202309.0131.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: BNT162b2 vaccine; Pfizer/BioNTech; cardiovascular events; COVID-19
Online: 4 September 2023 (08:19:54 CEST)
The analysis reported here is unique in that it is the first study of the original data from the Pfizer/BioNTech BNT162b2 mRNA vaccine clinical trial (CA4591001) to be carried out by a group unaffiliated with the trial sponsor. Our study is a forensic analysis of the 38 trial subjects who died between July 27, 2020, the start of Phase 2/3 of the clinical trial, and March 13, 2021, the data end date of their 6-Month Interim Report. Phase 2/3 of the trial involved 44,060 subjects who were equally distributed into two groups and received Dose 1 of either the BNT162b2 mRNA vaccinated or the Placebo control (0.9% normal saline). At Week 20, when the BNT162b2 mRNA vaccine received Emergency Use Authorization from the U.S. FDA, subjects in the placebo arm were given the option to be BNT162b2 vaccinated. All but a few accepted. Surprisingly, a comparison of the number of subject deaths per week during the 33 Weeks of this study found no significant difference between the number of deaths in the vaccinated versus placebo arms for the first 20 weeks of the trial, the placebo-controlled portion of the trial. After Week 20, as subjects in the Placebo were unblinded and vaccinated, deaths among this still unvaccinated cohort of this group slowed and eventually plateaued. Deaths in the BNT162b2 vaccinated subjects continued at the same rate. Our analysis revealed inconsistencies between the subject data listed in the 6-Month Interim Report and publications authored by Pfizer/BioNTech trial site administrators. Most importantly, we found evidence of an over 3.7-fold increase in number of deaths due to cardiovascular events in BNT162b2 vaccinated subjects compared to Placebo controls. This significant adverse event signal was not reported by Pfizer/BioNTech. Potential sources of these data inconsistencies are identified.
ARTICLE | doi:10.20944/preprints202202.0333.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: antibody; BNT162b2; coronavirus disease 2019; severe acute respiratory syndrome coronavirus 2; vaccine hesitancy; vaccine booster
Online: 25 February 2022 (10:01:23 CET)
This was a retrospective cohort study, which aimed to investigate the factors associated with hesitancy to receive the third dose of coronavirus disease 2019 (COVID-19) vaccine. A paper-based questionnaire survey was administered to all participants. Accordingly, the study included participants who provided answer in the questionnaire whether they have an intent to receive the third dose of vaccine. Data on sex, age, area of residence, adverse reactions after the second vaccination, whether the third vaccination was desired, and reasons to accept or hesitate booster vaccination were retrieved. Among the 2439 participants with mean (±SD) age of 52.6±18.9 years, and median IgG-S antibody titer of 324.9 (AU/mL), 97.9% of participants indicated their intent to accept a third vaccination dose. The logistic regression revealed that younger age (OR=0.98; 95% CI: 0.96-1.00) and higher antibody level (OR=2.52; 95% CI: 1.27-4.99) are positively associated with the third vaccine hesitancy. The efficacy of the COVID-19 vaccine and concerns about adverse reactions had significant impact on the third vaccination behavior. A rapid increase in the booster dose rate is needed to control the pandemic, and specific approaches should be taken in these groups that are likely to hesitate the third vaccine, subsequently increasing booster contact rate.
REVIEW | doi:10.20944/preprints202311.1643.v1
Subject: Public Health And Healthcare, Health Policy And Services Keywords: COVID-19; SARS-CoV-2; vaccine; vaccine efficacy; vaccine effectiveness, vaccine booster; BNT162b2; mRNA1273; Ad26.COV2.S; ChAdOx1-S; SARS-CoV-2 variants
Online: 28 November 2023 (01:41:16 CET)
We study here what can be learned from our experience with COVID-19 vaccination for an initially naïve population, that can inform planning for vaccination against the next novel, highly transmissible pathogen. We focus on the first two pandemic years (wild strain through Delta), because after the Omicron wave in early 2022, few people were still SARS-CoV-2-naïve. Almost all were vaccinated, infected, or often both. We review the evidence on COVID-19 vaccine effectiveness (VE), waning effectiveness over time, and what we should expect about VE and waning from a future pathogen. As a basis for our analysis, we conducted a PRISMA-compliant review of all studies on PubMed through August 15, 2022 reporting VE against four endpoints: any infection, symptomatic infection, hospitalization, and death, for the four principal vaccines used in developed Western countries (BNT162b2, mRNA1273, Ad26.CoV2.S, and ChAdOx1-S). The mRNA vaccines (BNT162b2, mRNA1273) had high initial VE against all endpoints but protection waned after approximately six months, with BNT162b2 declining faster than mRNA1273. Both mRNA vaccines initially outperformed the viral vector vaccines. A third “booster” dose, roughly six months after the primary doses, substantially reduced symptomatic infection, severe disease, and mortality, and in hindsight should be seen as part of the normal vaccination schedule.
ARTICLE | doi:10.20944/preprints202309.0788.v1
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: adverse effects; anti-SARS-CoV-2 antibody kinetics; BNT162b2 vaccine; breakthrough infections; COVID-19
Online: 13 September 2023 (02:44:35 CEST)
Background: Vaccination is one of the most effective life-saving medical interventions, and the introduction of SARS-CoV-2 vaccines was intended to prevent the serious implications of COVID-19. The objectives of the study were: i) to observe the humoral immune response to BNT162b2 vaccine and SARS-CoV-2 infection (mainly breakthrough infections), ii) to demonstrate the persistence of anti-SARS-CoV-2 antibodies over time in relation to the number of received vaccine doses and the course of infection, and iii) to determine adverse effects after primary vaccine doses. Methods: To assess the humoral response, IgG and IgA anti-S1 antibodies were quantified by ELISA assays. In total, the tests were carried out seven times in almost two years. Results: We demonstrated strong immunogenicity (compared to levels before primary vaccination, 150- and 20-fold increases in IgG and IgA, respectively) of the BNT162b2 vaccine. Over time, we observed a systematic decline in antibody levels, which may have contributed to breakthrough infections. Although they caused seroconversion similar to the booster, antibody levels in such patients fell more rapidly than after re-vaccination. On the other hand, in individuals who did not receive booster(s) and who did not present breakthrough infection, anti-SARS-CoV-2 antibodies returned to pre-vaccination levels after 20 months. The most commonly recognized adverse effects were injection site redness and swelling. Conclusion: Vaccination is highly effective in preventing the most severe outcomes of COVID-19 and should be performed regardless of prior infection. Booster doses significantly enhance anti-SARS-CoV-2 antibody levels and, in contrast to those obtained by breakthrough infection, they remain longer.
ARTICLE | doi:10.20944/preprints202308.1899.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: SARS-CoV-2; BNT162b2 vaccine; cancer patients; anti-neoplastic treatment; chemotherapy; antibodies; immunogenicity.
Online: 29 August 2023 (03:49:55 CEST)
The BNT162b2 vaccine is globally used for preventing morbidity and mortality related to COVID-19. Cancer patients have had priority for receiving the vaccine due to their diminished immunity. This study reports the response of administering the 3rd and 4th vaccine doses to can-cer patients receiving active anti-neoplastic treatment. 142 patients have received two doses of the mRNA-based BNT162b2 COVID-19 vaccine, while 76 and 25 patients have received three and four doses, respectively. The efficacy of the humoral response following two vaccine doses was diminished in cancer patients, especially in the group of patients receiving chemotherapy. In a multivariate analysis, patients after three and four BNT162b2 vaccine doses were more likely to have antibody titers in the upper tertile compared to patients after two doses of the vaccine (odds ratio (OR) 7.62 (95% CI 1.38-42.12), p=0.02 and 17.15 (95% CI 5.01-58.7), p<0.01, respective-ly). Unlike the response after two doses, the 3rd and 4th BNT162b2 vaccine booster doses, had an increased efficacy of 95-100% in cancer patients while on active treatment. This result could be explained by different mechanisms including the development of memory B cells.
ARTICLE | doi:10.20944/preprints202207.0286.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: SARS-CoV-2; Omicron variant of concern; homologous boosting; heterologous boosting; Coro-naVac; BNT162b2; healthcare worker; return-to-work
Online: 19 July 2022 (10:15:39 CEST)
Immune escape is observed with SARS-CoV-2 Omicron (Pango lineage B.1.1.529), the predominant circulating strain worldwide. Booster dose was shown to restore immunity against Omicron infection, however, real world data comparing mRNA (BNT162b2; Comirnaty) and inactivated vaccine (CoronaVac; Sinovac) homologous and heterologous boosting is lacking. A retrospective study was performed to compare the rate and outcome of COVID-19 in healthcare workers (HCWs) with various vaccination regime during a territory-wide Omicron outbreak in Hong Kong. During the study period 1 Feb – 31 Mar 2022, 3167 HCWs were recruited, 871 HCWs reported 746 and 183 episodes of significant household and non-household close contact. 737 HCWs acquired COVID-19 which were all clinically mild. Time dependent Cox regression showed that, comparing with 2-dose vaccination, 3-dose vaccination reduced infection risk by 31.7% and 89.3% in household contact and non-household close contact respectively. Using 2-dose BNT162b2 as reference, 2-dose CoronaVac recipient had significantly higher risk of being infected (HR 1.69 P<0.0001). Three-dose BNT162b2 (HR 0.4778 P<0.0001) and 2-dose CoronaVac + BNT162b2 booster (HR 0.4862 P=0.0157) were associated with lower risk of infection. Three-dose CoronaVac and 2-dose BNT162b2 + CoronaVac booster were not significantly different from 2-dose BNT162b2. The mean time to achieve negative RT-PCR or E gene cycle threshold 31 or above was not affected by age, number of vaccine dose taken, vaccine type and timing of the last dose. In summary, we have demonstrated lower risk of breakthrough SARS-CoV-2 infection in HCWs given BNT162b2 as booster after 2 doses of BNT162b2 or CoronaVac.
ARTICLE | doi:10.20944/preprints202208.0463.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: COVID-19 vaccines; vaccine effectiveness; BNT162b2 vaccine; mRNA-1273 vaccine; ChAdOx1 vaccine; 19 Elecsys Anti-SARS-CoV-2 S assay; reactogenicity; vaccine-associated symptoms
Online: 26 August 2022 (14:14:39 CEST)
This prospective study provides data on long-term humoral immunogenicity of a heterologous off-label vaccine regimen combining the adenoviral vectored ChAdOx1 nCoV-19 from Astra-Zeneca (ChAd) with the mRNA-1273 vaccine from Moderna (m1273) in comparison to two different homologous mRNA vaccine schedules. Of the 316 COVID-19 naïve adult health care workers (HCW) included to complete a survey on vaccine-associated symptoms (VAS), 197 had received the homologous BNT162b2 mRNA vaccine from Pfizer/BioNTech (BNT/BNT), 76 the homologous m1273/m1273, and 43 the heterologous ChAd/m1273 vaccine regimen. Concentration of antibodies against SARS-CoV-2 spike protein in plasma 5-7 months after the second vaccine dose was higher in the m1273/m1273 and ChAd/m1273 than the BNT/BNT vaccine group. The frequency of systemic VAS after first vaccine dose was 86% after ChAd compared to 35% and 39% after BNT and m1273, respectively (p < 0.0001), and after second vaccine dose highest (89%) in the m1273/m1273 group (p < 0.001). Individuals with systemic VAS achieved higher levels of antibodies irrespective of vaccine regimen. In conclusion, VAS serve as a strong predictor of long-term humoral immune response, and the heterologous ChAd/m1273 vaccine regimen provides an at least equal long-term humoral immune response compared with the standard vaccine regimens used in Denmark.
ARTICLE | doi:10.20944/preprints202309.0842.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: BNT162b2; efficacy; safety; neutralizing IgG antibodies; 25–hydroxyl vitamin D
Online: 13 September 2023 (05:33:42 CEST)
Background: BNT162b2 represents the authorized mRNA vaccine against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS–CoV–2) causing Covid–19. Methods: We conducted a prospective, single–center observational study with 273 employees of a medical facility to determine the efficacy and safety of the BNT162b2 third dose in relation to sex and BMI, and explore the possible determinants of neutralizing IgG and 25–hydroxy (25–OH) vitamin D levels. Results: At the median follow–up of 4.7 months, 38 of the participants had Covid–19 following vaccination. The incidence of adverse events (AEs) was significantly higher in females vs. males (p < 0.0108) and subjects with a high BMI of ≥ 30 kg/m2 vs. low BMI (p < 0.0117). The values of IgG were significantly enhanced in males vs. females (p < 0.0004), participants with high BMI vs. low BMI (p < 0.0003), a high number of ≥3 AEs vs. low number of AEs (p < 0.0003), and following infection with Covid–19 vs. without Covid–19 (p < 0.0005). Multivariate analysis (MVA) showed sex, BMI, number of AEs, and Covid-19 to be of predictive significance. On the contrary, 25–OH vitamin D concentrations in individuals with high vs. low BMI were significantly reduced (p < 0.0144) but this was not evident in MVA. Conclusions: This study confirmed the high efficacy of BNT162b2 in real–world scenario and revealed that its safety was affected by sex and BMI. Higher IgG levels suggesting better protection against infection were present in males, participants with high BMI, a high frequency of AEs, and those who overcame Covid-19 following vaccination.
ARTICLE | doi:10.20944/preprints202210.0057.v2
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: COVID-19; BNT162b2; vaccination; S-RBD; SARS-CoV-2; seroconversion
Online: 1 December 2022 (10:22:30 CET)
The humoral response of the COVID-19 vaccine varies from person to person. It largely depends on prior SARS-CoV-2 infection, obtaining an adequate immune response, and leaving a trace of changing antibody concentration over time. We retrospectively analyzed five clinical cases from selected patients and employees of the oncology hospital. All mild COVID-19 convalescents received the BNT162b2-Comirnaty mRNA vaccine three or four times. The levels of SARS-CoV-2 IgM- and IgG-specific antibodies, as well as S-RBD antibodies, were analyzed for two years. The concentration of antibodies was assessed in the laboratory using the chemiluminescent immunoassay CLIA, MAGLUMI. Results: (1) Active autoimmune disease stabilized the level of IgG-specific antibodies after systemic mRNA vaccination for at least six months. (2) Post-vaccination IgG and S-RBD levels decreased when vaccination was performed within three months of onset. (3) The booster dose administered only increased the S-RBD antibody levels. Declining IgG-specific antibodies were observed. (4) The S-RBD IgG levels were not correlated with the SARS-CoV-2 IgG levels in the vaccinated convalescents. (5) Subsequent reinfection with SARS-CoV-2 after vaccination three times released a more significant specific antibody response. Based on the collected data, we suggest that monitoring S-RBD antibodies is sensitive but not equivalent to a specific humoral response for SARS-CoV-2 IgG. We suggested that administering at least three doses of the mRNA vaccine should serve as the basis for immunization. The three-month interval may be the best alternative to an immunization schedule for non-immunocompromised people.
ARTICLE | doi:10.20944/preprints202106.0237.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: SARS-CoV-2; vaccine; BNT162b2; antibody, serology; kinetic; age; gender; BMI; blood-group.
Online: 8 June 2021 (13:48:34 CEST)
Background: Little is known about potential confounding factors influencing the humoral response in individuals having received the BNT162b2 vaccine. Methods: Blood samples from 231 subjects were collected before and 14, 28 and 42 days following COVID-19 vaccination with BNT162b2. Anti-Spike Receptor-Binding-Domain protein (anti-Spike/RBD) immunoglobulin G (IgG) antibodies were measured at each time-point. Impact of age, sex, childbearing age status, hormonal therapy, blood group, body mass index and past-history of SARS-CoV-2 infection were assessed by multivariable analyses. Results and Conclusions: In naïve subjects, the level of anti-Spike/RBD antibodies gradually increased following administration of the first dose to reach the maximal response at day 28 and then plateauing at day 42. In vaccinated subjects with previous SARS-CoV-2 infection, the plateau was reached sooner (i.e. at day 14). In the naïve population, age had a significant negative impact on anti-Spike/RBD titers at day 14 and 28 while lower levels were observed for males at day 42, when corrected for other confounding factors. BMI as well as B and AB blood groups had a significant impact in various subgroups on the early response at day 14 but no longer after. No significant confounding factors were highlighted in the previously infected group.
ARTICLE | doi:10.20944/preprints202311.0182.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: Abdominal obesity, obesity, BMI, BNT162b2 mRNA vaccine, antibody response, IgG-TrimericS, booster dose, COVID-19
Online: 2 November 2023 (14:42:21 CET)
Little is known about the long-term durability of the induced immune response in subjects af-fected by obesity, particularly in those with an abdominal distribution of adipose tissue. We evaluated SARS-CoV-2-specific antibody response after BNT162b2 vaccine booster dose, com-paring individuals with abdominal obesity (AO) with those without, discerning between indi-viduals previously infected or not. IgG-TrimericS were measured in 511 subjects at baseline, 21 days after vaccine dose-1 and at one, three, six and nine months after dose-2 and at one and three months after booster dose. Nucleocapsid antibodies were assessed at baseline and at the end of the study to detect SARS-CoV-2 infection. To evaluate the three-months difference in absolute variation of IgG-TrmicericS levels from booster dose we used multivariable linear regression that showed interaction between AO and SARS-CoV-2 infection status (p=0.016). AO is associated with higher absolute IgG-TrimericS variation in prior infected individuals, regardless of possi-ble confounders and IgG-TrimericS levels at booster dose (p=0.0125). No interaction was evinced using BMI in the same regression model (p=0.418). The robust response in the development of antibodies after booster dose, observed in people with OA and previous infection, may support the recommendations to undergo the booster dose also in this population group.
ARTICLE | doi:10.20944/preprints202203.0411.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: COVID-19; SARS-CoV-2; Vaccines; anti-SARS-CoV-2 spike total antibodies; Surrogate viral neutralizing antibody; T-cell immune response; CoronaVac; ChAdOx1; BNT162b2; booster
Online: 31 March 2022 (14:28:11 CEST)
Inactivated SARS-CoV-2 vaccine (CoronaVac) is commonly used in national immunization programs. However, the immune response significantly declined within a few months. Our study assessed the immune response against SARS-CoV-2 after receiving booster shots of BNT162b2 or ChAdOx1 among health care workers who previously received CoronaVac as their primary immunization. Fifty-six participants received ChAdOx1 and forty-two participants received BNT162b2 were enrolled into this study which evaluated the immune responses including anti-SARS-CoV-2 spike total antibodies (Elecsys®), surrogated viral neutralization test (sVNT) to ancestral strain (cPass™; GenScript) and five variants of concern (Alpha, Beta, Gamma, Delta, and Omicron) (Luminex; multiplex sVNT) and the ELISpot with spike (S1 and S2) peptide pool against the ancestral SARS-CoV-2 strain. The samples were analyzed at baseline, 4, and 12 weeks after primary immunization as well as 4 and 12 weeks after receiving the booster. This study showed a significantly higher B-cell response among the BNT162b2 than the ChAdOx1 booster group, particularly against the Omicron variant, as well as a trend of good T-cell immune response in the BNT162b2 group. Moreover, the immune response rapidly declined at 12 weeks after the booster. A fourth dose or a second booster should be recommended, especially for reducing Omicron severity.