An Overview of the Sanofi/GSK COVID-19 Vaccine

COVID-19 vaccine

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Sanofi Pasteur and GlaxoKlineSmith were expecting to start phase 3 clinical trials for a vaccine to fight the novel coronavirus (COVID-19) in December, 2020. Instead, the pharmaceutical companies are revising plans for phase 2 of the vaccine after initial results weren't what they had hoped.

The combined effort between the two companies has Sanofi developing a vaccine using an adjuvant from GlaxoKlineSmith (GSK). While the initial hope was to have a vaccine ready be to considered for regulatory approval in early 2021, the protein-based recombinant vaccine didn't perform as well as hoped in early trials.

This sent the company's back to the lab to rework the formula, and they are now requesting a re-do of the second phase of the clinical trial, with plans to compare the vaccine to one of the vaccines already approved--like Pfizer's or Moderna's--rather than a placebo.

How It Works

The Sanofi/GSK vaccine candidate is a recombinant protein-based vaccine based on the baculovirus, commonly found in moths. Pieces of the novel coronavirus are used in combination with the baculovirus to effectively program the immune system to better recognize and fight COVID-19. There are a number of other recombinant vaccines in development from other pharmaceutical companies.

Sanofi is working on a second type of COVID-19 vaccine, too. The second effort involves a messenger RNA (mRNA) vaccine, which uses strands of genetic material to teach the immune system new strategies to recognize and fight disease. That vaccine is still in the very early stages, and won't even begin early clinical trials until 2021.

How Effective Is It?

In initial, early stage trials, Sanofi reports that the company's recombinant vaccine had similar antibody levels as people aged 18 to 48 who had had COVID-19 and developed antibodies naturally.

In older adults above age 48, however, the vaccine underperformed. In that group, the antibody levels generated by the vaccine were less than in people with natural immunity.

The companies have tested a number of combinations of one and two doses of vaccine, as well as different adjuvants. After reviewing these early-stage results, Sanofi/GSK are now requesting approval for a phase 2B trial, which will use an amended formula.

The companies want to test the reformulated vaccine against another approved vaccine rather than a placebo. According to Sanofi, the reformulated vaccine has been shown to be protect lungs against the damage COVID-19 causes when tested in animals.

When Will It Be Available? 

With approval of the phase 2B trial plan, the Sanofi and GSK hope to begin the next phase of testing by February 2021. This means that later phase trials and regulatory approval wouldn't come until much later in 2021.

Who Can Get the Sanofi/GSK Vaccine?

Sanofi and GSK are working on developing vaccines for adults at the moment, with no word yet on when testing will being in children and teen populations.

Research on the vaccine has been delayed by the need for reformulation, but even if the vaccine were on track, who gets the vaccine and when is a question that can only be answered by government regulators.

The Centers for Disease Control and Prevention (CDC) is leading vaccination efforts, and all orders of the COVID-19 vaccine regardless of the manufacturer will go through the agency. CDC is overseeing the distribution of vaccines, too.

CDC’s Advisory Committee on Immunization Practices (ACIP) has made recommendations on how to prioritize vaccine supplies. Healthcare workers and people living in long-term care facilities will be the first to receive the first of the vaccines, which will be limited at first as manufacturing ramps up.

According to the CDC, there are more than 21 million healthcare providers in the U.S., and about 3 million Americans living in long-term care facilities. Each of these people would need to receive two doses of the top vaccine contenders so far, totaling nearly 50 million doses needed for the initial phase of vaccination alone.

The CDC estimates it will take several months before the supply of vaccines catches up to the demand. Guidance on who will receive the vaccine and when will be decided as supplies become available. The U.S. alone has a population of about 330 million—meaning nearly 700 million vaccine doses will be needed to vaccinate all of America if other vaccines follow a two-dose regimen.

Although little information is available yet on the specifics of when everyone will receive the vaccination, and where they can get it, state and local health departments will be coordinating efforts to distribute doses of the vaccines as they become available. The vaccine should be available both in physician offices and retail locations like pharmacies that administer other vaccines.

Once the vaccine is available, any doses purchased by the U.S. government will be free to its citizens. While the vaccine itself is free, the facility or agency that offers the vaccine may charge a fee for administration. Public health programs and insurance plans are expected to reimburse patients for any costs associated with COVID-19 vaccination, but not much information has been made available yet.

Side Effects and Adverse Events

Full results of the early phase trials haven't been published yet, but Sanofi says that there were no serious adverse events in the more than 400 people who participated in the first studies. Additional information will be provided as trials are advanced with the new formulation of the vaccine. No information has been released yet on Sanofi's mRNA vaccine.

Funding and Development

Sanofi and GSK are developing the recombinant vaccine with the help of government funding. In July 2020, the partnership was awarded $30 million through a program administered by the U.S. Department of Health and Human Services called the Biomedical Advanced Research and Development Authority (BARDA) and Operation Warp Speed.

BARDA is part awarding the funds in an effort to speed up how quickly vaccines to fight COVID-19 can be developed and approved for use. The agreement entitles the U.S. government to 100 million doses of the vaccine if approved, with another $2 billion in funds available for another 500 million doses, if the government decides to exercise its option for additional doses.

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