Abstract
This is the first study outside of clinical trials (phase I–III) evaluating the ability of the Ad5-nCoV vaccine to generate neutralizing antibodies and the factors associated with optimal or suboptimal response. In a longitudinal assay, 346 people (117 with prior COVID-19 and 229 without prior COVID-19) vaccinated with Ad5-nCoV were recruited. The percentage of neutralizing antibodies against SARS-CoV-2 (Surrogate Virus Neutralization Test) and antibodies against Ad5 (ADV-Ad5 IgG ELISA) were quantified pre and post-vaccination effects. The Ad5-nCoV vaccine induces higher neutralizing antibodies percentage in individuals with prior COVID-19 than those without prior COVID-19 (median [IQR]: 98% [97–98.1] vs. 72% [54–90], respectively; p < 0.0001). Furthermore, a natural infection (before vaccination) induces more neutralizing antibodies percentage than immunized individuals without prior COVID-19 (p < 0.01). No patient had vaccine-severe adverse effects. The age, antidepressant, and immunosuppressive treatments, reactogenicity, and history of COVID-19 are associated with impaired antibody production. The anti-Ad5 antibodies increased after 21 days of post-vaccination in all groups (p < 0.01). We recommend the application of a booster dose of Ad5-nCoV, especially for those individuals without previous COVID-19 infection. Finally, the induction of anti-Ad5 antibodies after vaccination should be considered if a booster with the same vaccine is planned.
Highlights
Since December 2019, coronavirus disease 2019 (COVID-19) has caused more than four million deaths worldwide [1], mainly in older adults and patients with underlying diseases such as diabetes, hypertension, obesity, lung diseases, and cardiovascular diseases [2].Innate immunity is the first line of defense against pathogens and induces adaptive immunity, which generates immunological memory [3]
This study aimed to determine the vaccine-associated side effects, the generation of neutralizing antibodies against SARS-CoV-2 and anti-Adenovirus 5 (Ad5) antibodies in a group of Mexican patients immunized with the Ad5-nCoV vaccine with and without a history of COVID-19
The subjects were classified into two groups: (1) individuals vaccinated without prior COVID-19 infection (n = 229), and (2) individuals vaccinated with previous COVID-19 infection (n = 117)
Summary
Since December 2019, coronavirus disease 2019 (COVID-19) has caused more than four million deaths worldwide [1], mainly in older adults and patients with underlying diseases such as diabetes, hypertension, obesity, lung diseases, and cardiovascular diseases [2].Innate immunity is the first line of defense against pathogens and induces adaptive immunity, which generates immunological memory [3]. The neutralizing antibodies rapidly appear in serum after SARS-CoV-2 infection and vaccination and are maintained for several months [5]. The evolution in technology and sequencing of the SARS-CoV-2 genome allowed the accelerated development of various vaccines types [6,7], including viral vector-based vaccines, mRNA and DNA vaccines, subunit vaccines, nanoparticle-based vaccines, and inactivated-whole virus vaccines [8]. Several of these vaccine types are being approved in record time to minimize the high lethality of this virus
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
