Vaccines, Equity, and Public Trust: A Front‑Line View from Seattle to CDC ACIP
Q&A with Helen Chu, MD, MPH
Helen Chu, MD, MPH is a Professor of Medicine in the Division of Allergy and Infectious Diseases at the University of Washington School of Medicine. She is an infectious disease physician and epidemiologist whose research focuses on respiratory virus surveillance, community transmission dynamics, and vaccine effectiveness. Dr. Chu served as a member of the CDC's Advisory Committee on Immunization Practices and was a key member of the team that identified the first cases of community transmission of COVID‑19 in the United States.
When first reports of a mysterious respiratory illness reached the United States, it was not a federal agency that detected community spread, but a group of researchers in Seattle. One of them was Dr. Helen Chu, an infectious disease physician and epidemiologist at the University of Washington whose work spans the clinic, the lab, and the intricacies of public health decision‑making. As COVID‑19 took hold, she and her colleagues helped uncover early transmission chains and generated some of the first real‑world data on how the virus moved through communities.
Later, as a member of the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP), Dr. Chu saw vaccine policy made from the inside. ACIP has long been the body that weighs evidence and recommends how vaccines should be used in the United States. Over the past year, however, the Committee has been abruptly reconstituted, with all 17 members dismissed and a new group appointed amid debate over conflicts of interest, expertise, and political influence.
This conversation with Dr. Chu follows earlier interviews in the Harvard ALI Social Impact Review with Dr. Rochelle Walensky, former CDC Director, and Dr. Camille Kotton, an infectious disease specialist and past ACIP member. Those discussions explored how public health leaders navigated crises, how ACIP is meant to function when it works well, and how trust can fray when science and politics collide. Here, we return to those themes from a different vantage point: that of a clinician‑scientist who helped detect the first sparks of a pandemic and then tried to translate evidence into vaccine policy for children, pregnant women, and the communities hit hardest.
Tom Mahoney, ALI Senior Fellow ’24, spoke with Dr. Chu about where the system has fallen short, what the data reveal about equity and gender, how vaccine platforms performed in the real world, and what a better decision‑making framework might look like going forward.
From Outbreak Detective to Vaccine Policymaker
Tom Mahoney: You helped detect some of the first community spread of COVID‑19 in Seattle and later served on ACIP, the CDC's vaccine advisory committee. When you look across that journey - from the clinic and lab to national policy - what feels most urgent to re‑examine in U.S. immunization policy today, and why does it matter for families now?
Dr. Helen Chu: One of the most urgent areas is to rethink how we translate evidence into clear, consistent immunization guidance for the public. During COVID-19, we saw how rapidly evolving science - around variants, waning immunity, and booster timing - led to complex and sometimes shifting recommendations. The data changed rapidly, and the communications around the changing data led to confusion and eroded public trust. We need a system that can adapt to the changing information around us but also be able to communicate more clearly about uncertainty to ensure that the public can trust our recommendations but also understand that the information that is given is based on the information available at the time and that is ever evolving.
When the System Falls Short
Mahoney: Readers have already heard from your former ACIP colleague Dr. Camille Kotton in these pages about how ACIP is supposed to work when it's functioning well. From your vantage point, where did you first see that system start to fall short - either in how evidence was weighed or in how decisions came under pressure - and what real‑world consequences did you worry about?
Chu: The dismissal of the ACIP signaled a fundamental shift away from what has historically made U.S. vaccine policy so rigorous - which was a stable, transparent, and evidence-driven process insulated from political pressure. For decades, that system was considered the global gold standard because it was built on open data review, rigorous conflict-of-interest safeguards, and a clear pathway from evidence to recommendation that was based on careful review of the data. The abrupt removal of the full Committee suggested that those guardrails were no longer in place. The new ACIP meetings were clearly held with a prespecified agenda of re-evaluating the evidence around all the vaccines, with the goal to make changes in vaccine recommendations to focus on individual decision-making rather than public health. The individuals who were appointed as the new members of the ACIP lacked the scientific expertise in vaccinology to interpret the data and to make these decisions.
Mahoney: To pursue the dismissal of all 17 ACIP members a bit further, a move some saw as reform and others as politicization, when you learned you were being removed, what did that move signal to you about the direction of vaccine decision‑making in the United States, especially for children and pregnant women?
Chu: The proceedings of the new ACIP have created uncertainty for families and clinicians. It is no longer the case that the best scientific evidence is being used to make vaccine policy. In fact, the shift to “individual decision-making” has led to people being incredibly confused about what vaccines are recommended, and about whether they are accessible or will be covered by health insurance. This can then lead to missed vaccinations, increased disease transmission, and increased risk for vulnerable household members, including pregnant women and children. The reliance on the childhood vaccine schedules from other countries, such as Denmark, is dangerous. The entire healthcare system of the United States is different from other countries, and the policies we have reflect the heterogeneity of our population. To summarily dismiss all of the data from the United States is shocking, and reflects the lack of understanding by the new ACIP of how nuanced decision-making is.
Equity in the Data
Mahoney: We know that COVID and other respiratory infections have not affected all communities equally - rates of infection, hospitalization, and death have often been higher in communities of color and in lower‑income neighborhoods. From the data you’ve worked with, what patterns stand out most clearly, and how should they have shaped vaccine policy and rollout?
Chu: It was clear from the beginning that the risk of severe COVID-19 was higher in lower-income communities - those who lived in high density multigeneration households, worked in frontline occupations, and who had limited access to healthcare. From the beginning, there was disparity in who could access vaccines. In the future, it would be important to prioritize the things that we know eventually worked to get vaccines into vulnerable communities - mobile clinics, community-partnerships, and trusted messengers.
Mahoney: When you look at who actually gets vaccinated, whether during the COVID pandemic or for other respiratory pathogens - who had easy access, who faced obstacles, who remained unprotected - what differences do you see between more‑privileged communities and lower‑income or historically marginalized groups, and how did those gaps show up later in outcomes?
Chu: The communities that had lower vaccine coverage had higher infection rates and more severe disease - reflected in higher rates of hospitalization and death and higher burden of long COVID. For other diseases, younger individuals with chronic underlying diseases, such as COPD, diabetes, and end stage renal disease, are at high risk for poor outcomes, traditionally are from vulnerable populations, and have lower vaccine rates.
Gender, Pregnancy, and Missing Evidence
Mahoney: Women, and especially pregnant women, often face different risks from infections, yet they have not always been fully represented in early vaccine studies. What do we know - and what do we still not know - about how vaccines have worked for women overall, and for women of color or lower‑income women in particular?
Chu: Pregnancy was traditionally an exclusion criterion for enrollment into clinical trials; thankfully the thinking around that has changed. We know that vaccines are safe and effective in pregnancy, and that they protect the pregnant woman, and in many cases, also protect the infant through antibody transfer across the placenta. Vaccine uptake for pregnant women follows the same patterns as vaccine uptake for non-pregnant women - white and Asian women receive vaccines at higher rates than other racial/ethnic groups - and this is reflected in outcomes of hospitalization and severe disease.
Mahoney: Pregnant women have frequently been caught between higher risk from infection and limited data on available vaccines. How did you think about recommendations for vaccinating pregnant women while you were at ACIP, and how do you view the recent decision to change the recommendation for COVID vaccination for healthy pregnant women to “individual decision making”?
Chu: These vaccines should not be given based on individual decision making. Many infections, such as flu and SARS-CoV-2, cause more severe disease in pregnant women and lead to adverse pregnancy outcomes, and there is extensive safety and efficacy data supporting the use of these vaccines in pregnancy. This is not a decision where the benefits and risks need to be weighed at the individual level - these vaccines have clear benefit, and the risk of severe disease is extremely high. The use of the term individual or shared clinical decision making implies that the risks and benefits may balance each other - one example is giving yellow fever vaccine to pregnant women. It is a live vaccine, which we usually don’t give in pregnancy, due to theoretical risk of infection of the fetus. However, yellow fever is a serious infection, and for women who are traveling to endemic places, then the benefit of vaccination to prevent infection may outweigh the theoretical risk of fetal infection. That is a situation where shared clinical decision making is appropriate. For flu or COVID vaccines that is not the case at all. These vaccines are safe, and they are highly protective.
Information, Misinformation, and Trust
Mahoney: During the pandemic, some communities heard consistent messages about vaccines from trusted sources, while others were left with conflicting or misleading information. In your experience, who had access to credible vaccine guidance, who did not, and how did those differences in information reinforce existing health inequities?
Chu: There were clear differences in where people received their information, and that influenced the type of information they received. There was also a divide politically in what information was trusted vs. what was thought to be false; what has been remarkably consistent is that people still trust their doctors and turn to them for vaccine advice. It has just become remarkably harder for doctors and other care providers to be able to stem the wave of disinformation that is all around them.
Mahoney: Parents and pregnant women have had to make decisions amid changing guidance and visible scientific uncertainty. When you sit with a hesitant parent or patient, how do you talk through a vaccine decision when the data are still evolving, and what have you learned about what builds trust - or breaks it - in those conversations?
Chu: I think it is important to understand what it is that people are afraid of - what their specific concerns are and to address those directly. For example, some people may want their vaccines spaced out, and we can have a conversation about how the immune system is able to handle multiple vaccines at one time, and that we really need to give these vaccines before the virus starts circulating in the community. Someone else may have heard that the vaccines contain toxins, and we can talk through what is in a vaccine and how all those ingredients work together and the process by which vaccines are made.
I think honesty is important and also being empathetic and hearing people’s concerns. What builds trust is being able to listen and understand where people are coming from, and to make sure that the patient understands that we both have the same goal - which is to keep them healthy and safe from vaccine-preventable diseases. However, as the provider, we have to be able to convey a strong recommendation for vaccines because patients trust us and expect us to take care of them.
Vaccine Platforms in the Real World
Mahoney: Looking across vaccine platforms - mRNA, protein‑based, and older technologies (e.g. live-attenuated, whole inactivated and viral vector vaccines) - what did real‑world patient data reveal that early clinical trials or models missed, particularly for children and pregnant women? Where did platforms perform better or worse than you expected?
Chu: Overall, the vaccines were safe and highly effective against severe disease and performed much better than we had initially expected them to.
In the post-licensure period there were rare adverse events, including myocarditis with the adolescent mRNA second dose and thrombosis with the adenovirus vectored vaccines; because of the rarity of these adverse events, it wasn’t until the post-licensure period that they were identified because it required millions of doses to be given for us to see these signals.
The early clinical trials showed extremely high efficacy overall, because of the lack of population immunity, and the close match between the viral strain in the vaccine and the circulating strain at the time, WA-1. As the virus evolved and as the population developed hybrid immunity, the vaccine effectiveness decreased, which is to be expected and is more in line with the seasonal vaccines we give, such as for flu.
The rapid waning of protection at 4-6 months was unexpected, as was the rapid evolution of the virus necessitating update in the strains in the vaccines on an annual basis.
Mahoney: If you were advising vaccine developers today, what lessons from real‑world outcomes would you want them to carry into the next generation of vaccines - for example, who must be included earlier in clinical trials, which outcomes need longer follow‑up, or how to anticipate rare but serious adverse events?
Chu: I think that we need to invest in understanding the mechanism underlying adverse events - and there needs to be funding for research in this space, so that we understand what the risk factors, and potentially early signals, are of these later events. For example, what if we could find a biomarker that predicts development of myocarditis. I think that would do a lot towards reassuring the public that we are taking these adverse events seriously and working to minimize the risks for future vaccine development.
I think we also need to message better about what these vaccines can and cannot do. They cannot provide sterilizing immunity, but what they can do is prevent severe disease and death.
We are also starting to see interesting signals in the ability of vaccines to prevent cardiopulmonary outcomes, such as heart attack and strokes, as well as prevention of dementia. If there is an opportunity to incorporate evaluation of these outcomes in longer-term studies of vaccines, I believe that this can provide real benefit to helping people understand both the short term and the long-term benefit of vaccination.
Rethinking Decision‑Making and Looking Ahead
Mahoney: If you could design a new national framework for vaccine recommendations from scratch - not just rebuild ACIP under a new name - what core functions, expertise, and safeguards would you insist on? And if we were having this conversation again in 2030, what concrete signs would tell you that vaccine policy is working better for children, pregnant women, and the communities that have historically been left behind by extant US immunization policy?
Chu: It is clear that we do need a national policymaking body. As we have seen in the past year, having no unified decision-making has led to confusion and chaos. The professional organizations have done a good job of stepping in to make recommendations, but there is only so much that they can do. So we do need the ACIP to exist.
To be able to future-proof the ACIP, we would need to put regulation in place that prevents the HHS director from having total discretion in the assembling of the vaccine advisory group, or in adopting its recommendations. Vaccine policy should not be subject to politics - these are scientific decisions that are made based on evidence - and if the general public perceives that this is no longer the case, then they will not trust them. One way to do this is to make the ACIP charter something that cannot be changed at the discretion of the HHS Secretary. The ACIP charter governs who can be on the committee, how often it meets, and its role in vaccine decision-making. Concrete signs would be improved health outcomes in these populations and elimination of vaccine -preventable diseases - it would mean the end of these ongoing measles outbreaks, the end of pertussis outbreaks, and equally high vaccine uptake in all groups.
Mahoney: Thank you, Dr. Chu, for sharing with us such an insightful - and incisive - traversal of the remarkable arc of your exemplary career devoted to courageous leadership in the field of public health in our country. Do you have any final thoughts - and especially, suggestions as to how you’d like to see immunization standards and practice evolve and improve - to attain superior patient outcomes for vaccine preventable illness, for all communities in the United States, over the next five to ten years?
Chu: I think we need to focus our efforts over the next several years on regaining the trust of the public. We need to think beyond the randomized clinical trials and the efficacy data to really focus on how we succeed at implementation. At the end of the day, we need to get vaccines in arms, and we are not doing a good job at that. For that, we need to invest in the research and the platforms to communicate clearly and to make it as easy as possible for people to get their vaccines.
About the Author:
Tom Mahoney, a 2024 Senior Fellow at the Harvard Advanced Leadership Initiative, is focused on global venture philanthropy initiatives to catalyze investment in development of breakthrough vaccines, therapeutics and diagnostics for infectious diseases. A career investment banker, technology entrepreneur and asset management senior executive, Tom is a member of the Advisory Board of EdJen BioTech, LLC, a developer of novel viral vaccines, and Virufy, a respiratory disease diagnostics platform; a Founding Sponsor of the Harvard Alumni Entrepreneurs Accelerator; and a member of the Venture Board of the Harvard HealthLab Accelerator, the Massachusetts Consortium on Pathogen Readiness, and the Council on Foreign Relations.