Sitting Down With... Moncef Slaoui

What inspired your interest in science, and how did you come to focus on biologics and vaccines?
 

My interest in science began early in life. I have always been fascinated by the complexity of the human body and living organisms, and I was eager to understand their mechanisms beyond the religious explanations provided in my early education. By the age of ten, I had developed a strong passion for biology, which ultimately drove me to pursue a career in science. While my initial ambition was to become a physician, I eventually pursued a PhD in immunology, which led me to the study of the immune system.  

My transition into vaccines was somewhat serendipitous. During my postdoctoral research in the US, my future wife, an HIV expert, was recruited by a vaccine company, which was a division of GlaxoSmithKline (GSK) in Belgium. As an immunologist, I began advising the company, and through that engagement, I developed a deep appreciation for vaccines.  

A personal factor also played a role in my commitment to vaccines; my parents lost a child to whooping cough before I was born. This tragedy instilled in my family a strong awareness of the importance of immunization. Over time, this awareness evolved into a lifelong professional passion. 

You have been involved in numerous vaccine projects. What do you consider the biggest challenges in the field?
 

Vaccine development has evolved significantly over the years. Historically, vaccines were produced by growing entire pathogens — bacteria or viruses — and then either killing or attenuating them for use in immunization. However, advances in immunology and molecular biology in the 1960s revolutionized the field. These breakthroughs enabled us to identify and utilize specific proteins from pathogens, allowing for more targeted and rational vaccine design.  

Despite these advances, several challenges remain. The first major challenge is overcoming pathogens that have evolved sophisticated mechanisms to evade the immune system. Viruses such as HIV and herpes, as well as bacteria such as chlamydia, have developed ways to subvert immune responses, making vaccine development for these diseases extraordinarily difficult.  

The second challenge lies in the complexities of large-scale vaccine manufacturing. Producing vaccines requires a high level of precision to ensure consistency across billions of doses. This demands advanced infrastructure, significant investment, and highly skilled personnel.  

A third and growing challenge is public trust. Vaccines are only effective if people accept and receive them. Unfortunately, misinformation has contributed to a decline in vaccine confidence, which is deeply concerning. Recent policy changes in the US may further exacerbate this issue, making it even more critical to engage in transparent and effective communication about the safety and necessity of vaccines.  

How did it feel to be involved in major vaccine projects like Shingrix and the malaria vaccine?
 

I feel incredibly fortunate to have played a role in these projects. My early involvement in vaccines happened largely by chance, but it became a deeply fulfilling career. Some vaccines, such as the malaria vaccine, took over 25 years to develop from initial concept to regulatory approval. The moment we receive key data demonstrating efficacy is profoundly emotional. I have often found myself overwhelmed with joy, sometimes even in tears, knowing that our work will save millions of lives.  

This impact is particularly meaningful in low-income countries, where access to life-saving vaccines can determine survival for large populations. When I was an executive at GSK, I ensured the company remained committed to developing vaccines and medicines that were not necessarily lucrative but were crucial for global health. The malaria vaccine, for example, was never designed to generate profit – it was designed to save hundreds of thousands of children’s lives each year in sub-Saharan Africa.  

How did you become involved in Operation Warp Speed, and what was the experience like?
 

My involvement stemmed from prior collaborations with the US government during previous health crises, including the H1N1 flu pandemic in 2008, the Ebola outbreak, and the Zika virus outbreak. During those events, I strongly advocated for better pandemic preparedness. Unfortunately, little action was taken at the time.  

When COVID-19 emerged, former congressman Jim Greenwood reached out to me, and after a 45-minute discussion on how to accelerate vaccine development, he informed me that the White House would likely call. Within days, I was in discussions with senior government officials, including Jared Kushner and Alex Azar. I agreed to lead the scientific efforts of what was initially called the “Manhattan Project 2,” later known as “Operation Warp Speed”.  

The first major decision was selecting which vaccines to support. Over 100 candidates were submitted, but I narrowed them down to six based on my experience and intuition. Fortunately, all six turned out to be highly effective. The program involved thousands of professionals across pharmaceutical companies, the US Army, and various agencies. It was an intense, high-pressure experience, but ultimately, we achieved our goal of delivering vaccines in record time.  

Given the current political climate, do you feel your efforts were in vain?
 

Not at all. Our work was never just for the US, it was for the world. Approximately six billion people have been vaccinated, saving tens of millions of lives. While political controversies and misinformation have been frustrating, I remain confident in the vaccines’ effectiveness and safety. The rapid development process was rigorous, and after billions of doses, we know these vaccines are both safe and critical in preventing disease. Science enabled us to reclaim normalcy, and that is something to be proud of.  

How did you become involved with Abzena, and what excites you about the company?
 

Since retiring from GSK, I have been active in venture capital, supporting biotech companies. Abzena caught my attention because it operates at the intersection of discovery and manufacturing, offering expertise in designing complex biologics and bioconjugates, with the capability to produce them at scale. Their ability to bridge these two critical areas is invaluable, particularly in the era of advanced biopharmaceuticals such as bispecific and trispecific antibodies, antibody-drug conjugates (ADCs), antibody-oligonucleotide conjugates (AOCs), and radiopharmaceuticals.  

What trends in biopharma particularly interest you?
 

I am especially excited about engineered antibodies, which are revolutionizing oncology and immunoinflammatory diseases. Additionally, cell therapies hold immense potential, though manufacturing remains a significant hurdle. Vaccines remain a core passion, and I continue to monitor new technologies in that space.  

With Donald Trump back in office, do you anticipate significant policy changes?
 

Every administration brings changes, and while I have had many interactions with President Trump, my focus is on science, not politics. My priority is to contribute where I can to advancing healthcare and making scientific progress. Scientists should engage with policymakers constructively while maintaining scientific integrity.