According to details of a study released on Thursday, August 5, Moderna has revealed its Covid-19 vaccine booster shot produced a “robust” antibody response against the highly contagious delta variant.

In its phase two trial, Moderna tested a 50-microgram dose of three vaccine booster candidates in previously vaccinated individuals. The booster shots produced a promising immune response against three variants, including delta, with antibody levels approaching those seen in previously unvaccinated people who received two 100-microgram doses.

The data has been submitted to a peer-reviewed journal for publication, according to Moderna.

The company’s second-quarter financial results beat Wall Street’s expectations on earnings and revenue. Here’s how Moderna did compare with what Wall Street expected, according to average estimates compiled by Refinitiv:

• Earnings per share: $6.46 versus $5.96 expected
• Revenue: $4.35 billion versus $4.2 billion expected

The new data on boosters comes as the delta variant spreads across several countries, including Nigeria. The Centers for Disease Control and Prevention has said the variant is as contagious as chickenpox and may make older people sicker, even if they’ve been fully vaccinated.

Moderna also added that a final analysis of its phase three study found the two-dose vaccine was 93% effective, with efficacy “remaining durable” through six months after the second dose.

By comparison, Pfizer and BioNTech said their vaccine efficacy declined to around 84% six months after the second shot.