Dalila Zizi's research while affiliated with University of Oxford and other places

Publications (6)

Article
Full-text available
p>More than 190 vaccines are currently in development to prevent infection by the novel severe acute respiratory syndrome coronavirus 2. Animal studies suggest that while neutralizing antibodies against the viral spike protein may correlate with protection, additional antibody functions may also be important in preventing infection. Previously, we...
Article
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Background The ChAdOx1 nCoV-19 (AZD1222) vaccine has been approved for emergency use by the UK regulatory authority, Medicines and Healthcare products Regulatory Agency, with a regimen of two standard doses given with an interval of 4–12 weeks. The planned roll-out in the UK will involve vaccinating people in high-risk categories with their first d...
Article
Full-text available
Background A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. Methods This analysis includes dat...
Article
Older adults are at higher risk of severe disease and death if they develop COVID-19 and are therefore a priority for immunisation should an efficacious vaccine be developed. Immunogenicity of vaccines is often poorer in older adults as a result of immunosenescence. We recently reported the immunogenicity of a novel viral vectored vaccine, ChAdOx1...
Article
Full-text available
Background Older adults (aged ≥70 years) are at increased risk of severe disease and death if they develop COVID-19 and are therefore a priority for immunisation should an efficacious vaccine be developed. Immunogenicity of vaccines is often worse in older adults as a result of immunosenescence. We have reported the immunogenicity of a novel chimpa...

Citations

... AZD1222 vaccinees who experienced breakthrough infections displayed robust anamnestic IgG responses, which correlated with reduced viral loads and durations of viral shedding in saliva. Although we and others have observed transient increases in NELF IgA levels from vaccinees with prior SARS-CoV-2 infection (22,41,43), intramuscular vaccination with adenovirus-and mRNA-based COVID-19 vaccines does not appear to induce anamnestic NELF IgA responses in SARS-CoV-2-seronegative vaccinees despite eliciting IgA responses in serum (43)(44)(45). These findings suggest that different approaches (e.g., use of adjuvants, other delivery routes) will be required to improve mucosal immunogenicity for currently licensed COVID-19 vaccines (46). ...
... Currently, four vaccines are approved for use against covid-19 in the European Union and these are manufactured by Pfizer-BioNTech (Comirnaty) [57], Moderna [58], Oxford-AstraZeneca (Vaxzevria) [59,60], and, most recently, Janssen [61]. Interestingly, unrecognized nanotechnology reached clinical trials before the established approach (i.e., live attenuated and inactivated vaccines) reaching clinical trials and, if proven successful, could enable a faster response to emerging infectious diseases in the future. ...
... Vaccine candidates have been generated by recombinant protein expression, delivery of viral vectors, virus-like particles, or nucleic acids. All above mentioned approaches have elicited robust immune responses in immunized animals and in many cases provided protection against SARS-CoV-2 challenges in rodents and primates ( [104] expressing the full-length SARS-CoV-2 S protein provided protection against challenges with SARS-CoV-2 in macaques after two immunizations. In an approach to reduce any immune response against the adenovirus vector itself leading to compromised vaccine efficacy, a prime-boost strategy of prime vaccination with Ad26-SARS-CoV-2 S followed by Ad5-SARS-CoV-2 vaccination showed efficacy in preclinical animal models [107]. ...
... The effect of age on tolerability, has also been reported following both authorised mRNA vaccines, 9,10 and the Oxford-Astra Zeneca COVID-19 vaccine. 11 Those at lowest risk of a life-threatening illness were most likely to experience a severe reaction which may deter individuals from completing the regimen at a population level. There was no association between age and immune responses which were similar in all age groups. ...
... SARS-CoV-2 vaccines relying on novel technologies, including RNA (5-7) and vectors (8,9), have proved highly effective in controlling severe Covid-19 requiring hospitalizations and have changed the course of the pandemic. Yet, they put demand on the infrastructure, requiring establishment of cold-chains, which make them less attractive for mass-vaccination in developing countries. ...
... According to the CDC, general concern about vaccines has increased alongside rapid global vaccine production (12). Like other vaccines, the Oxford/AstraZeneca vaccine was developed rapidly but has been proven to be safe in phase studies (13, 14,15). Despite this, there have been delays in the administration of the second dose because of the worldwide impact of the negative news about the Oxford/AstraZeneca vaccine (16,17). ...