Frequently Asked Questions

Last update: March 12, 2021

What makes Sanofi’s COVID-19 programs different from others? 

Sanofi’s vaccine division Sanofi Pasteur has nearly 100 years of experience in the development and delivery of vaccines. We are not only developing effective COVID-19 vaccines, but also to manufacturing them on a massive scale and ensuring they will be accessible and affordable around the world. We are uniquely positioned to do so in several ways:

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  • We are pursuing two different vaccine candidates in parallel to increase chances of success and maximize production capacities to help meet worldwide demand.
  • We are doing so in unique partnerships with industry peers, including GSK (for the recombinant protein vaccine) and Translate Bio (for the mRNA vaccine) as well as governments, including the US and EU.
  • One of our vaccine candidates is developed with well-established, recombinant-protein technology already used effectively in influenza vaccines.
  • The fact that this vaccine technology is well established also means the distribution channels and methods are already in place to help ensure availability of high-volume supply.
  • We have a massive vaccine manufacturing and pharmaceutical industrial footprint, which is being scaled up with support from partners and governments worldwide.

How can Sanofi assess safety with accelerated development timelines?

Monitoring and evaluating the safety of any investigational vaccine is of utmost priority. The development of a vaccine candidate will continue only if its risk/benefit profile remains acceptable, as with any new vaccine. 

In the development of COVID-19 vaccines, safety controls are no different from what we normally do for any new vaccine candidate. We are working with regulatory authorities to ensure all required safety data are collected and an Independent Data and Monitoring Committee will be integrated in our development programs. Sanofi Pasteur is accelerating the process in other areas, for example some clinical trial phases will overlap one another to shorten the total development time. Regulatory authorities are also helping by reviewing data in real time throughout clinical trials and prioritizing new COVID-19 vaccine reviews. We are carrying out full safety monitoring that occurs in all our clinical trials, which includes rigorous and objective scientific review of safety and efficacy data prior to any regulatory agency’s approval of our COVID-19 vaccines.

Why aren’t Sanofi COVID-19 vaccines first to market? 

No one company, nor one technology can address this problem alone, and for us it’s never been about a race to be first. Ending a pandemic requires a global collaborative effort, and the more approaches and partnerships that move forward the more we will increase our chances of success. 

We continue to rapidly respond to the evolving challenge of COVID-19 and we are exploring all vaccine options as part of these efforts, including pursuing two different technological approaches to help increase odds of success. We are following the science in the pursuit of our vaccine candidates with multiple partners, on the timelines each initiative requires to give us the best chance of bringing COVID-19 vaccines to people worldwide.

What does it mean for a vaccine to be less than 100% effective?

Efficacy rates are estimates scientists make when observing clinical trials. In those trials, they compare the number of people in a group of vaccinated participants who may still become infected with COVID-19, with the number of people in a control group who have received a placebo and who have become infected with COVID-19. The efficacy percentage indicates the likelihood the vaccine will protect a person from infection. The World Health Organization (WHO) has established a target product profile for COVID-19 vaccines, including optimal efficacy levels at less than 100% (and a minimum of 50%). Even with vaccines that achieve less than 100% efficacy in clinical trials, a significant number of hospitalizations and severe cases would be averted.

How will Sanofi’s vaccines be allocated to people around the world?

We will work with our partners, GSK and Translate Bio, governments and NGOs to ensure our COVID-19 vaccine(s), if and when approved, will be available worldwide. Financial systems such as the Advance Purchase Agreements have been established to help support and extend our production capacities for the recombinant protein vaccine candidate. As part of these agreements, governments can secure quantities of vaccines for their populations. This is the case for the US, the EU, the UK and Canada.   

In addition, the international public health community has organized a global pooled procurement mechanism called the COVAX Facility (led by the WHO, Gavi and others). COVAX helps participating countries gain access to the vaccine in an efficient and optimally equitable way. We are participating in this Facility and will continue discussions with WHO, Gavi and partners as the pandemic and vaccine project development evolve.

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How does Sanofi plan to manufacture so many doses of COVID-19 vaccines without disrupting regular business or diverting from other activities?

Our COVID-19 activities are in addition to all our pre-existing activities and we continue to both receive new market authorizations for new drugs and vaccines as well as meet our product supply commitments around the world. Sanofi benefits from a large global R&D and industrial footprint that we are extending across our manufacturing sites in the US and in Europe to support COVID-19 vaccine projects. We are also partnering with GSK for their adjuvant on the recombinant protein vaccine initiative and with Translate Bio on the mRNA initiative, and these partners’ capacities greatly support scaleup. In addition, new ramp up is supported by new financial systems such as Advance Purchase Agreements, established to quickly support the extension of our production capacities, and as part of the agreements, governments can secure quantities of vaccines for their populations.

What will your clinical trials show for the recombinant protein adjuvanted vaccine candidate?

The phase 1/2 study interim results for the recombinant protein adjuvanted vaccine candidate showed an immune response comparable to patients who recovered from COVID-19 in adults aged 18 to 49 years, but a low immune response in older adults, likely due to an insufficient concentration of the antigen. On February 22 we announced initiation of a new phase 2 study of our adjuvanted recombinant protein COVID-19 vaccine candidate. The study will evaluate the candidate's safety, reactogenicity, and immunogenicity and if successful, will support selection of the most appropriate antigen dosage for phase 3. For more information, see our recent press release.

Positive results from this study would lead to regulatory submissions in the second half of 2021, with the vaccine’s potential availability in Q4 2021.

Sanofi routinely publishes key protocol details on clinical trial registries such as and full protocols and statistical plans are also shared at the time of publication of study results.

Due to the exceptional nature of the COVID-19 pandemic, we will make available our protocols before each phase begins. Read more on the protocol for our new phase 2 here.

Where are Sanofi’s clinical trials being held and where can I learn more?

For the adjuvanted recombinant protein vaccine candidate, the new phase 2 study is being held in the United States and Honduras. Selection of study sites is made based on available epidemiological data on covid-19 circulation and availability of research sites with whom we have existing relationships. Phase 3 will be conducted in multiple countries around the world. 

For the vaccine using mRNA technology, we announced the start of 1/2 clinical trials on March 12.

Are you able to manufacture COVID-19 vaccines of other companies?

It is our responsibility towards public health to contribute to solving the COVID-19 pandemic in every way possible. While our utmost priority remains to advance our two COVID-19 programs, we have offered our temporarily available capacities to support manufacturing and supply of BioNTech’s approved COVID-19 vaccine which is co-developed with Pfizer, the vaccine developed by Johnson and Johnson and the vaccine developed by Moderna. We are planning to start producing and delivering doses from summer 2021 onward.

When will Sanofi’s vaccines be available? 

We are following the science in the development of our two vaccine projects. Concerning the recombinant protein vaccine, if data from our new phase 2 trial are positive, a global phase 3 study could start in Q2 2021. Positive results from the phase 3 would lead to regulatory submissions in the second half of 2021, with the vaccine’s potential availability in Q4 2021. Our other vaccine using mRNA technology entered into phase 1/2 clinical trials on March 12.