COVID-19 Vaccine Leaders Make Progress on Omicron-Specific Boosters

Companies creating COVID-19 vaccines are progressing in designing and testing Omicron-specific booster shots, as one of the key concerns about the Omicron variant and subvariants of the SARS-CoV-2 virus that causes COVID-19 is its ability to evade immunity.

Luckily, it does not appear more deadly than the original Wuhan wildtype strain or the following variants, such as Delta. But studies have shown that the Omicron variant and subvariants can evade antibody responses of people who are fully vaccinated and boosted, as well as people who had previous COVID-19 infections. The current vaccinations still offer significant protection against severe cases.

Moderna’s Bivalent COVID-19 Booster Candidate

Moderna announced clinical data last week on its bivalent COVID-19 booster candidate, mRNA-1273.214. This vaccine includes the original formulation but also has a vaccine targeting Omicron. In studies, it increased neutralizing titers against BA.4/BA.5 by 5.4-fold above baseline regardless of the previous infection and by 6.3-fold in the subset of seronegative patients.

The company is planning to submit the data to regulators soon, with expectations of it being distributed by August.

Stephane Bancel, Moderna’s chief executive officer, said, “In the face of SARS-CoV-2’s continued evolution, we are very encouraged that mRNA-1273.214, our lead booster candidate for the fall, has shown high neutralizing titers against the BA.4 and BA.5 subvariants, which represent an emergent threat to global public health.”

Pfizer-BioNTech’s 2 Omicron-Adapted Vaccines

Over the weekend, Pfizer and BioNTech announced positive data on two Omicron-adapted COVID-19 vaccine candidates. One is bivalent, with just a focus on Omicron, while the other is a combination of their original vaccine and a candidate targeting the Omicron BA.1 variant of concern. Data from the Phase II/III trial demonstrated that a booster shot of either vaccine stimulated a substantially higher immune response against Omicron BA.1 than their original vaccine. It was seen across two dose levels, 30 micrograms and 60 micrograms.

“As we’ve said since the early days of the pandemic, we will follow the science and adapt our own approaches as needed to help address COVID-19 as the virus evolves,” Albert Bourla, Pfizer’s chairman and chief executive officer, said. “Based on these data, we believe we have two very strong Omicron-adapted candidates that elicit a substantially higher immune response against Omicron than we’ve seen to date. We look forward to discussing these data with the scientific community and health authorities so we may rapidly introduce an Omicron-adapted booster as soon as possible if authorized by regulators.”

Clover’s Omicron BA.2-Focused Booster

Shanghai, China-based Clover Biopharmaceuticals announced positive data in people receiving a third dose of SCB-2019, a homologous booster against the Omicron variant. A third shot of the vaccine demonstrated a 19-fold increase in neutralizing antibody levels against the Omicron BA.2 variant compared to pre-booster levels.

“This highly encouraging homologous booster data against Omicron represents a key milestone on Clover’s path to developing SCB-2019 for primary vaccination and as a universal COVID-19 booster vaccine to protect individuals in need, regardless of previous vaccination technology or infection history,” Joshua Liang, chief executive officer and executive director of Clover, said in a statement. 

GSK and Sanofi’s Clinical Studies for Next-Gen COVID-19 Booster

Sanofi and GlaxoSmithKline announced data from two clinical studies, VAT02 Cohort 2 and COVIBOOST VAT013. The trials were evaluating their next-generation COVID-19 booster vaccine that uses a Beta variant antigen and GSKJ’s pandemic adjuvant.

The Phase III VAT02 Cohort 2 trial demonstrated an increase in antibody titers above baseline 15 days after receiving the vaccine against multiple variants of concern in adults who previously received the Pfizer-BioNTech or Moderna shots. And it demonstrated a 40-fold increase against the original Omicron variant, BA.1 and doubled the number of neutralizing antibodies against Omicron BA.1 and BA.2 compared to the D614, the original parent virus booster. The COVIBOOST study, dosed after the Pfizer-BioNTech shots, induced a higher immune response than the Pfizer-BioNTech booster or the Sanofi-GSK first-generation booster.