Symptomatic SARS-CoV-2 Infection with Ageusia after Two mRNA Vaccine Doses

To raise awareness about preventive measures in COVID-19 pandemic, even though fully vaccinated. Although recent trials showed high efficacy of vaccines in preventing symptomatic infections, there are some individuals experiencing symptomatic SARS-CoV-2 infection. In this case report, a fully vaccinated young dental practitioner experienced symptomatic SARS-CoV-2 infection 55 days postvaccination with BNT162b2 Pfizer vaccine with evident ageusia. Diagnostic swabs were performed and used for viral genome sequencing. The patient fully recovered 15 days after diagnosis. Loss of smell and taste, together with nasal congestion were the main reported symptoms. The use of personal protective equipment prevented spread of infection in patients and co-workers. With the increase of people being fully vaccinated, it is still necessary to follow infection preventive protocols by correctly applying personal protective equipment. Although high efficacy has been proved, some individuals may still be vulnerable to symptomatic infection and new guidelines and markers should be adopted and investigated to find out patients for whom vaccination may not determine full immunization.

Summaries, Analysis and Simulations of COVID-19 Epidemics in Shanghai

Shanghai is the best city to prevent the spread of COVID-19 infection in China. Since February 20, 2020, Shanghai has experienced five waves of COVID-19. Out of a total of 388 patients with COVID-19 symptoms, 381 were cured and seven died. Medical staff achieved zero infection. This paper summarizes, analyzes and simulates COVID-19 epidemics in Shanghai. The simulation results show that for five waves of epidemics, after reaching the infection turning point, the blocking rate of symptomatic infection is over 99%. The administration needs to maintain the prevention and control implemented 7 days after reaching the infection turning point until the new infection goes away.

The incidence of COVID-19 infection following emergency use authorization of BBIBP-CORV inactivated vaccine in frontline workers in the United Arab Emirates

Based on the findings from the Phase III clinical trials of inactivated SARS COV-2 Vaccine, (BBIBP-CORV) emergency use authorization (EUA) was granted for the vaccine to frontline workers in the UAE. A prospective cohort study was conducted among frontline workers to estimate the incidence rate and risk of symptomatic COVID-19 infection 14 days after the second dose of inoculation with BBIBP-CORV inactivated vaccine. Those who received two doses of the BBIBP-CORV vaccine in the period from 14th of September 2020 (first dose) to 21st of December 2020 (second dose) were followed up for COVID-19 infections. 11,322 individuals who received the two-dose BBIBP-CORV vaccine were included and were followed up post the second dose plus fourteen days. The incidence rate of symptomatic infection was 0.08 per 1000-person days (95% CI 0.07, 0.10). The estimated absolute risk of developing symptomatic infection was 0.97% (95% CI 0.77%, 1.17%). The confirmed seroconversion rate was 92.8%. There were no serious adverse events reported and no individuals suffered from severe disease. Our findings show that vaccinated individuals are likely to remain protected against symptomatic infection or becoming PCR positive for SARS COV 2 following the second dose of the vaccination.

COVID-19 vaccine effectiveness among healthcare workers in Portugal: results from a hospital-based cohort study, December 2020 to November 2021

Introduction: Healthcare workers (HCW) were amongst the first prioritized for COVID-19 vaccination but data on COVID–19 vaccine effectiveness among HCW is still limited. This study aims to estimate the COVID–19 vaccine effectiveness (VE) against SARS–CoV–2 symptomatic infection among HCW from Portuguese hospitals. Methods: In this prospective cohort study, we analysed data from HCW (all professional categories) from two central hospitals in the Lisbon and Tagus Valley and Centre regions of mainland Portugal between December 2020 and November 2021. VE against symptomatic SARS–CoV–2 infection was estimated as one minus the confounder adjusted hazard ratios by Cox models considering age group, sex, presence of chronic disease and occupational exposure to patients diagnosed with COVID–19 as adjustment variables. Results: During the 11 months of follow up, the 2213 HCW contributed a total of 1950 person-years at risk and 171 SARS–CoV–2 events occurred. The COVID–19 incidence rate for unvaccinated HCW was 348.7 per 1000 person-years while for fully vaccinated HCW was 43.0 per 1000 person-years. We observed a VE against symptomatic SARS–CoV–2 infection of 73.9% (95% CI: 26.2–90.8%) for complete vaccination status. Conclusion: This cohort study found a high COVID-19 VE against symptomatic SARS–CoV–2 infection in Portuguese HCW, which is in concordance with previous studies from other countries. Monitoring of VE in this HCW cohort continues during the winter 2021/2022 to evaluate potential VE decay and booster vaccine effect. Keywords: Vaccine effectiveness, SARS–CoV–2 , COVID–19, symptomatic infection, healthcare workers.

Waning Effectiveness of the BNT162b2 Vaccine Against Infection in Adolescents

Background: The short-term effectiveness of a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 vaccine for adolescents has been demonstrated. However, little is known about the long-term effectiveness in this age group. It is known, though, that waning of vaccine-induced immunity against infection in adult populations is evident within a few months. Methods: Leveraging the centralized computerized database of Maccabi Healthcare Services (MHS), we conducted a matched case-control design for evaluating the association between time since vaccination and the incidence of infections, where two outcomes were evaluated separately: a documented SARS-CoV-2 infection (regardless of symptoms) and a symptomatic infection (COVID-19). Cases were defined as individuals aged 12 to 16 with a positive PCR test occurring between June 15 and December 8, 2021, when the Delta variant was dominant in Israel. Controls were adolescents who had not tested positive previously. Results: We estimated a peak vaccine effectiveness between 2 weeks and 3 months following receipt of the second dose, with 85% and 90% effectiveness against SARS-CoV-2 infection and COVID-19, respectively. However, in line with previous findings for adults, waning of vaccine effectiveness was evident in adolescents as well. Long-term protection conferred by the vaccine was reduced to 75-78% against infection and symptomatic infection, respectively, 3 to 5 months after the second dose, and waned to 58% against infection and 65% against COVID-19 after 5 months. Conclusions: Like adults, vaccine-induced protection against both SARS-CoV-2 infection and COVID-19 wanes with time, starting three months after inoculation and continuing for more than five months.

Safety and efficacy of the Novavax vaccine—a narrative review

Mass vaccination programs are a public health priority for managing the global coronavirus disease (COVID-19) pandemic. The NVX-CoV2373 vaccine is being developed by Novavax. It consists of a SARS-CoV-2 spike glycoprotein subunit (NVX-CoV2373), which has been shown to have structural stability with pH and temperature perturbations, and the saponin-based Matrix-M adjuvant, which is added to enhance the B- and T-cell-mediated immune response. Animal studies in mice, olive baboons, and cynomolgus macaques demonstrated the potential of this vaccine in protecting the respiratory tract against COVID-19. Subsequent phase 1 and 2 trials then confirmed its safety and the dose-sparing potential of Matrix-M. The results led to the use of a low dose (5 μg) of NVX-CoV2373 in phase 3 trials. In a phase 3 trial involving 14,039 participants, the vaccine efficacy rate was 89.7% (prevention of symptomatic infection). Local and systemic adverse events were mild and self-limiting; commonly reported symptoms included injection-site pain and tenderness, headache, myalgia, and fatigue. A subgroup study confirmed the safety and efficacy of co-administering the NVX-CoV2373 vaccine and the seasonal influenza vaccine. Overall, the vaccine has been found to be safe and effective, meeting the minimum vaccine efficacy rate of 50% to be considered for COVID-19 vaccine emergency use listing approval. Keywords: Clinical trials, COVID-19, COVID-19 vaccine, immunology

Effectiveness of CoronaVac, ChAdOx1, BNT162b2 and Ad26.COV2.S among individuals with prior SARS-CoV-2 infection in Brazil

Background. COVID-19 vaccines have proven highly effective among SARS-CoV-2 naive individuals, but their effectiveness in preventing symptomatic infection and severe outcomes among individuals with prior infection is less clear. Methods. Utilizing national COVID-19 notification, hospitalization, and vaccination datasets from Brazil, we performed a case-control study using a test-negative design to assess the effectiveness of four vaccines (CoronaVac, ChAdOx1, Ad26.COV2.S and BNT162b2) among individuals with laboratory-confirmed prior SARS-CoV-2 infection. We matched RT-PCR positive, symptomatic COVID-19 cases with RT-PCR-negative controls presenting with symptomatic illnesses, restricting both groups to tests performed at least 90 days after an initial infection. We used multivariable conditional logistic regression to compare the odds of test positivity, and the odds of hospitalization or death due to COVID-19, according to vaccination status and time since first or second dose of vaccines. Findings. Among individuals with prior SARS-CoV-2 infection, vaccine effectiveness against symptomatic infection ≥ 14 days from vaccine series completion was 39.4% (95% CI 36.1-42.6) for CoronaVac, 56.0% (95% CI 51.4-60.2) for ChAdOx1, 44.0% (95% CI 31.5-54.2) for Ad26.COV2.S, and 64.8% (95% CI 54.9-72.4) for BNT162b2. For the two-dose vaccine series (CoronaVac, ChAdOx1, and BNT162b2), effectiveness against symptomatic infection was significantly greater after the second dose compared with the first dose. Effectiveness against hospitalization or death ≥ 14 days from vaccine series completion was 81.3% (95% CI 75.3-85.8) for CoronaVac, 89.9% (95% CI 83.5-93.8) for ChAdOx1, 57.7% (95% CI -2.6-82.5) for Ad26.COV2.S, and 89.7% (95% CI 54.3-97.7) for BNT162b2.

Effectiveness of complete primary vaccination against COVID-19 at primary care and community level during predominant Delta circulation in Europe: multicentre study analysis by age-group, vaccine brand and time since vaccination, I-MOVE-COVID-19 and ECDC networks, July–August 2021

IntroductionIn July and August 2021, the SARS-CoV-2 Delta variant dominated in Europe. We measured COVID-19 vaccine effectiveness (VE) against symptomatic infection, using a multicentre test-negative study at primary care/community level in Europe.MethodsPatients presenting with COVID-19/ARI symptoms at primary care/community level in 10 countries were tested for SARS-CoV-2. We measured complete primary course overall VE among those aged 30–44, 45–59, 60–74 and ≥75 years, and among those 30–59 and ≥60 years by vaccine brand and by time since vaccination.ResultsOverall VE was 74% (95%CI: 69–79), 76% (95%CI: 71–80), 63% (95%CI: 48–75), 63% (95%CI: 16–83) among those aged 30–44, 45–59, 60–74 and ≥75 years, respectively. VE among those aged 30–59 years was 78% (95%CI: 75–81), 66% (95%CI: 58–73), 91% (95%CI: 87–94) and 52% (95%CI: 40–61), for Comirnaty, Vaxzevria, Spikevax and COVID-19 Vaccine Janssen, respectively. VE among those aged ≥60 years was 67% (95%CI: 52–77), 65% (95%CI: 48–76), 83% (95%CI: 64–92) for Comirnaty, Vaxzevria and Spikevax, respectively. Comirnaty VE among those aged 30–59 years was 87% (95%CI: 83–89) and 65% (95%CI: 56–71%) at 14–29 days and ≥90 days between vaccination and onset of symptoms, respectively.ConclusionsVE against the symptomatic SARS-CoV-2 Delta variant infection varied among brands, ranging from 52–91%. While some waning of the vaccine effect may be present (sample size limited this analysis to only Comirnaty), protection was 65% ≥90 days between vaccination and onset.

Effectiveness of the WHO-Authorized COVID-19 Vaccines: A Rapid Review of Global Reports till 30 June 2021

Large clinical trials have proven the efficacy of the COVID-19 vaccine, and the number of studies about the effectiveness rapidly grew in the first half of the year after mass vaccination was administrated globally. This rapid review aims to provide evidence syntheses as a means to complement the current evidence on the vaccine effectiveness (VE) against various outcomes in real-world settings. Databases (PubMed, EMBASE, and MedRxiv) were searched up to 30 June 2021, (PROSPERO ID: 266866). A total of 39 studies were included, covering over 15 million participants from 11 nations. Among the general population being fully vaccinated, the VE against symptomatic SARS-CoV-2 infection was estimated at 89–97%, 92% (95% CI, 78–97%), and 94% (95% CI, 86–97%) for BNT162b2, ChAdOx1, and mRNA-1273, respectively. As for the protective effects against B.1.617.2-related symptomatic infection, the VE was 88% (95% CI, 85.3–90.1%) by BNT162b2 and 67.0% (95% CI, 61.3–71.8%) by ChAdOx1 after full vaccination. This review revealed a consistently high effectiveness of certain vaccines among the general population in real-world settings. However, scarce data on the major variants of SARS-CoV-2 and the shortness of the study time may limit the conclusions to the mRNA vaccines and ChAdOx1.

Waning of mRNA-1273 vaccine effectiveness against SARS-CoV-2 infection in Qatar

BACKGROUND: In early 2021, Qatar launched a mass immunization campaign with Moderna mRNA-1273 COVID-19 vaccine. We assessed persistence of real-world mRNA-1273 effectiveness against SARS-CoV-2 infection and against COVID-19 hospitalization and death. METHODS: Effectiveness was estimated using test-negative, case-control study design, between January 1 and December 5, 2021. Effectiveness was estimated against documented infection (a PCR-positive swab, regardless symptoms), and against any severe (acute-care hospitalization), critical (ICU hospitalization), or fatal COVID-19. RESULTS: By December 5, 2021, 2,962 breakthrough infections had been recorded among those who received two mRNA-1273 doses. Of these infections, 19 progressed to severe COVID-19 and 4 to critical, but none to fatal disease. mRNA-1273 effectiveness against infection was negligible for the first two weeks after the first dose, increased to 65.5% (95% CI: 62.7-68.0%) 14 or more days after the first dose, and reached its peak at about 90% in the first three months after the second dose. Effectiveness declined gradually starting from the fourth month after the second dose and was below 50% by the 7th month after the second dose. Effectiveness against severe, critical, or fatal COVID-19 reached its peak at essentially 100% right after the second dose, and there was no evidence for declining effectiveness over time. Effectiveness against symptomatic versus asymptomatic infection demonstrated the same pattern of waning, but effectiveness against symptomatic infection was consistently higher than that against asymptomatic infection and waned more slowly. CONCLUSIONS: mRNA-1273-induced protection against infection appears to wane month by month after the second dose. Meanwhile, protection against hospitalization and death appears robust with no evidence for waning for several months after the second dose.