Safety and immunogenicity of Moderna vaccines containing mRNA encoding the spike protein of various SARS-CoV-2 strains
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In a latest examine posted to the medRxiv* preprint server, researchers evaluated the security and immunogenicity of coronavirus illness 2019 (COVID-19) vaccines towards extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs).

Study: SARS-CoV-2 Variant Vaccine Boosters Trial: Preliminary Analyses. Image Credit: rawf8/Shutterstock


COVID-19 vaccine-induced immune safety wanes with time, a problem compounded by the continuous emergence of SARS-CoV-2 variants. Booster doses of current vaccines, directed towards the SARS-CoV-2 spike (S) protein of the prototype Wuhan-Hu-1 pressure, might improve short-term vaccine effectiveness (VE); nonetheless, variant-specific SARS-CoV-2 vaccines can be required for sturdy immune safety towards SARS-CoV-2 VOCs. 

About the examine

In the current preliminary evaluation or first stage of section 2 randomized medical trial, researchers evaluated Moderna vaccines containing messenger ribonucleic acid (mRNA) encoding the S protein of a number of SARS-CoV-2 strains to evaluate the breadth, magnitude, and sturdiness of early antibody responses to second booster vaccination towards SARS-CoV-2. 

The evaluation was carried out between 30 March and 6 May 2022 throughout 22 websites within the United States (US) and enrolled wholesome adults who had obtained major SARS-CoV-2 vaccinations and one booster vaccination. For all eligible sufferers, prior SARS-CoV-2 an infection and the final vaccination dose had been ≥16 weeks earlier than the randomization course of. Previous SARS-CoV-2 infections had been thought of if the prognosis was based mostly on antigen checks, polymerase chain response (PCR) checks, or the presence of antibodies towards the SARS-CoV-2 nucleocapsid (N) protein as much as 27 June 2022 (information cut-off).

The examine members had been randomized to obtain considered one of six Moderna COVID-19 mRNA vaccine arms (50µg dose): prototype or mRNA-1273, Omicron BA.1+Beta (single/double dose), Omicron BA.1+Delta, Omicron BA.1 monovalent, and Omicron BA.1+Prototype. SARS-CoV-2 neutralization titers had been assessed. In addition, a randomly chosen subset (20 to 24 samples per vaccine arm) was analyzed for Omicron BA.2.12.1 and BA.4/BA.5 sublineage neutralization.

Pseudotyped lentivirus assays had been carried out with SARS-CoV-2 S mutations in D614G, Delta, Beta, Omicron BA.1, Omicron BA.2.12.1, and Omicron BA.4/BA.5 strains after 15 days of vaccination to find out the neutralization titers, expressed as ID50 (serum inhibitory dilution required for 50% neutralization) values. Electrochemiluminescence immunoassays had been used for measuring baseline anti-SARS-CoV-2 N titers.

Additionally, antigenic cartography evaluation was carried out, and antibody landscapes had been assessed. The systemic solicited opposed occasions (AEs) had been famous for one-week post-vaccination, and unsolicited AEs had been reported until day 29. Serious opposed occasions (SAEs), medically attended opposed occasions (MAAEs), and opposed occasions of particular curiosity (AESIs) noticed within the trial had been famous. 


A complete of 597 vaccinated members had been randomized, the median age of whom was 53 years, most of them (53%) had been girls, and 20% had prior COVID-19 historical past. All mRNA vaccines had been discovered well-tolerated and secure. Baseline and Day 15 geometric imply titers (GMT) had been comparable between older (≥ 65 years) and youthful grownup people in all vaccine arms however two-fold to three-fold greater amongst people with prior SARS-CoV-2 infections.

Day 15 GMTs towards the D614G pressure had been comparable throughout vaccine arms and age teams and better amongst these with prior SARS-CoV-2 infections. Among the uninfected examine members, Day 15 Omicron BA.1 GMTs for all Omicron-containing vaccine arms had been comparable (3724-4561) and had been greater than these for the prototype (1,997).

The Omicron BA.1+Prototype vaccine and the Omicron BA.1 monovalent vaccine induced geometric imply ratios (GMR) to prototype for Omicron BA.1 of 1.6 and a pair of.0, respectively. The Omicron BA.4/BA.5 neutralizing GMTs on day 15 had been one-third of these of Omicron BA.1. GMTs for prototype, Omicron BA.1+Beta, Omicron BA.1+Delta, and Omicron BA.1+Prototype had been 517, 628, 765 and 635, respectively.

For uninfected members, all vaccine arms had similar pre-vaccination antigenic landscapes, apexed over the D614G pressure. Post-vaccination, all arms had greater antibody titers with flattening of the antigenic panorama noticed. The second dose of COVID-19 mRNA booster vaccination raised antibody titers amongst uninfected members such that the titers had been much like these noticed amongst members with earlier SARS-CoV-2 infections. The largest improve was famous for anti-Omicron BA.1 titers by Omicron-containing mRNA vaccines. In the subset evaluation, the Omicron BA.1 + prototype and Omicron BA.1 + Delta mRNA vaccines elicited the very best titers; nonetheless, Omicron BA.1 + Beta vaccines flattened the antigenic landscapes probably the most.

Solicited AEs submit mRNA vaccination had been much like these noticed in earlier booster vaccination trials and didn’t considerably differ between the vaccine arms. Injection-site ache (83%) was the commonest solicited native AE, and probably the most often reported solicited systemic AEs had been myalgia (58%) and fatigue (67%). Importantly, most solicited AEs had been delicate (47%) or average (43%), and solely 4% had been extreme. In addition, 65 breakthrough SARS-CoV-2 infections had been reported after randomization; nonetheless, none required hospital admissions.

Overall, the examine findings confirmed higher titers towards Omicron BA.1 with the administration of Omicron-containing mRNA vaccines in comparison with the prototype mRNA vaccine and the anti- Omicron BA.4/BA.5 titers had been decrease than the anti-Omicron BA.1 titers for all of the candidate COVID-19 vaccines. The findings point out higher immunogenicity of strain-specific SARS-CoV-2 vaccines in comparison with prototype vaccines, warranting the necessity for updating COVID-19 vaccines.

*Important discover

medRxiv bioRxiv publishes preliminary scientific experiences that aren’t peer-reviewed and, due to this fact, shouldn’t be considered conclusive, information medical apply/health-related habits, or handled as established info.

Journal reference:

  • Branche, A. et al. (2022) “SARS-CoV-2 Variant Vaccine Boosters Trial: Preliminary Analyses”. medRxiv. doi: 10.1101/2022.07.12.22277336. material/10.1101/2022.07.12.22277336v1

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