Johnson & Johnson Submits New Data Showing Single-Shot Ad26.COV2.S Vaccine Elicits Durable Neutralizing Activity Against Delta and Other SARS-CoV-2 Variants

Recently, Johnson & Johnson announced that the latest research findings demonstrate its single-dose COVID-19 vaccine, Ad26.COV2.S, exhibits robust and durable activity against the rapidly spreading Delta variant as well as other widely circulating SARS-CoV-2 variants. Furthermore, data from another study indicate that the vaccine-elicited immune response persists for at least eight months. Both studies have been submitted to the preprint server bioRxiv.

Ad26.COV2.S, developed by Johnson & Johnson, is a COVID-19 vaccine that utilizes an adenovirus serotype 26 (Ad26) vector to express the SARS-CoV-2 spike protein. It provides protective efficacy with a single dose and has been granted Emergency Use Authorization (EUA) by the U.S. FDA.

In a preprint study submitted by Johnson & Johnson, researchers evaluated the neutralizing capacity of serum from eight volunteers participating in the Phase 3 clinical trial. Serum was obtained on Day 71 following administration of a single dose of Ad26.COV2.S.

Researchers used lentiviral vectors to express the spike proteins of different SARS-CoV-2 variants and assessed the neutralizing capacity of serum using a pseudovirus neutralization assay.

The trial results showed that, compared with the control B.1 strain, neutralizing titers in volunteer sera against SARS-CoV-2 variants decreased to varying degrees. Against the Delta (B.1.617.2) variant, neutralizing titers showed a 1.6-fold reduction, while against the Beta (B.1.351) and Gamma (P.1) variants, the reductions were 3.6-fold and 3.4-fold, respectively.

▲ Neutralizing titers of volunteer sera against different SARS-CoV-2 variants following a single dose of Ad26.COV2.S (Image source: Reference [2])

The researchers stated in the paper that this study indicates the decline in serum neutralizing activity against the Delta variant among Ad26.COV2.S recipients is less pronounced than that against the Beta and Gamma variants. This finding aligns with the serum responses observed in recipients of other COVID-19 vaccines. Previously, Ad26.COV2.S demonstrated robust protective efficacy against severe COVID-19 in a clinical trial conducted in South Africa, where over 95% of sequenced cases were identified as Beta variant infections. Consequently, in the discussion section, the researchers noted that a single dose of Ad26.COV2.S is likely to maintain protective efficacy against the Delta variant, as the neutralizing antibody level required for protection against Delta may be lower than that needed for Beta.

According to a press release from Johnson & Johnson, in another study submitted to bioRxiv by Dr. Dan Barouch of Beth Israel Deaconess Medical Center and his colleagues, scientists tracked the antibody and cellular immune responses of 20 volunteers enrolled in the Phase 1/2 clinical trial of Ad26.COV2.S. They found that the antibody and cellular immune responses persisted for at least eight months.

Furthermore, neutralizing antibody levels against multiple variants of concern listed by the World Health Organization increased over time following vaccination. The mean neutralizing antibody titer detected at 8 months post-vaccination was higher than that measured at 29 days post-vaccination. The SARS-CoV-2 variants tested by the researchers included Delta, Beta, Gamma, Alpha (B.1.1.7), Epsilon (B.1.429), and Kappa (B.1.617.1).

References:

[1] Positive New Data for Johnson & Johnson Single-Shot COVID-19 Vaccine on Activity Against Delta Variant and Long-lasting Durability of Response. Retrieved July 2, 2021, from https://www.jnj.com/positive-new-data-for-johnson-johnson-single-shot-covid-19-vaccine-on-activity-against-delta-variant-and-long-lasting-durability-of-response?utm_source=twitter_feed&utm_medium=organic&utm_campaign=deltavariant_pressrelease&utm_content=innovationpillar

[2] Jongeneelen et al., (2021). Ad26.COV2.S elicited neutralizing activity against Delta and other SARS‐CoV‐2 variants of concern. bioRxiv, https://doi.org/10.1101/2021.07.01.450707.

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