New Year’s Letter from Dr. Marc Lipsitch, CCDD Director

Dear colleagues, alumni, and friends,

As we start the new year, it is a privilege to write to you with some reflections on 2020, a year like no other, and to offer some perspective on the year ahead.

I lead the Center for Communicable Disease Dynamics at the Harvard Chan School. Our group consists of me, Drs. Caroline Buckee, Bill Hanage and Michael Mina, about 15 postdocs and 15 PhD and master’s students. Beyond this group is a set of top-notch collaborators around the School and University, like Drs. Yonatan Grad and Mauricio Santillana, and beyond, across the country and the world, including many alumni who are receiving this letter. Our research centers around improving methods to model the spread of infectious disease, and communicating that information to decision makers. If there ever was a true moment for affirming the value of our work, this is it. And that’s a good thing, because we’re all very tired.

In early February, the New York City Health Department asked our Center to create a simulation of COVID-19 case introductions in the U.S. and of different scenarios for how it could spread or not. We came back with a simple little model where one could turn the dials to see what happens. It was purely a hypothetical exercise, but they paid attention, and according to reporters who’ve followed this story, it made a big difference to how New York City prepared for and responded to the explosion of cases that followed in April.

We’ve done a lot of research since then, which I’m very proud of. My CCDD colleague Dr. Caroline Buckee has been leading a network using mobile phone data for tracking COVID-19 spread. She’s arguably the global authority in this area, using methods she’s refined through her research on infectious disease spread in low income settings globally. I find it fitting that she is applying this research from places like Bangladesh to the US, demonstrating that nowhere is immune, and the universal principle that we are indeed all connected. Dr. Bill Hanage has been studying the genomic fingerprint of COVID-19, collaborating with social epidemiologists to document the changing pattern of COVID-19’s disparate impacts by race and ethnicity, and advancing the use of wastewater monitoring to assess transmission of the virus. Dr. Michael Mina has been pioneering an idea for a Global Immunological Observatory—a weather forecasting system for infection—and has been vocal advocate for cheap, fast and easy rapid testing, rapid vaccine rollout, and other cutting-edge ideas that can save lives. I’ve focused on highlighting the consequences of spread for hospital capacity, modeling the consequences of social distancing, and providing an evidence base for how to allocate vaccines. All of us have placed special emphasis on public communication through countless op-eds and interviews with the press, providing solid scientific information (including what we don’t yet know) to the public and helping to fill the gaps left by inadequate Federal Government communication. We’ve also all been serving on advisory committees about aspects of the pandemic response from our local schools to state and national bodies and the World Health Organization.

I speak for all of us, in saying that the amount of active research and hard thinking we’ve done in the last 11 months, feels equivalent to many years’ worth of work. We’re not alone of course.

A reporter recently asked me what positives have come out of this pandemic. I have been privileged to be a member of the Massachusetts Vaccine Prioritization Group—a group of political officials, health care leaders, public health officials, academics, and community leaders. The mandate of the Group – which also includes our former dean, Barry Bloom, and is chaired by Harvard Chan faculty member Paul Biddinger – is to determine how to equitably distribute the COVID-19 vaccine doses the state receives from the Federal Government. By the end of 2020, almost 300,000 vaccine doses had been shipped to Massachusetts, and distribution has begun to health care workers and those in care facilities; first responders will start getting vaccinated next week.  More will follow in the coming months – not fast enough, but remarkable that we are at this point less than a year into the pandemic. I have been profoundly impressed by the level of care and professionalism, thoughtful prioritizing, respectful dialogue (and disagreement), and old-fashioned group problem solving by this group, which is united by one goal—to save lives and preserve public health. In a year of political and social division, it gives hope to work with such a committed group.

As a COVID-19 vaccine becomes available in 2021, here are a few things we can expect, and good public health advice:

  • The vaccine will be two doses, at least 3 or 4 weeks apart, depending on the manufacturer. The first dose appears, from limited available data, to provide considerable protection, but full protection comes after the second dose.
  • Side effects are common but temporary, especially after the second dose. You might feel tired, sore, or feverish. This is a normal and natural response. Isolate yourself if you’re feeling sick, just as you would normally.
  • The trials show that the vaccine is effective in preventing COVID illness, but it’s possible that one can still spread the virus, thus
  • Social distancing and various kinds of closures will be in place for many more months, even after vaccination. No change yet.

Apart from the good news of the vaccine in the US, there are also many other important developments on the horizon. It will be essential to get vaccines to countries around the world that have not locked in supplies early on. WHO and its partners are working toward that end, but the world must redouble its efforts at production and distribution to make sure that vaccines are distributed globally according to need, not just ability to pay.

Two new “variants of concern” of the SARS-CoV-2 virus have begun spreading, most notably one found in the UK initially and now documented in about 3 dozen countries. There is strong evidence that this variant is more contagious than the original virus, though so far no evidence that it is more harmful to those infected. There is good reason to expect it will spread widely and has the potential to make control efforts much harder – even the measures that worked last year to control spread could be inadequate to stop the spread of this new, more transmissible strain. In a nice example of how work on one pathogen can help with others, we have repurposed studies from CCDD on surveillance for antibiotic resistance to help the incoming Administration understand how to conduct surveillance for this new strain. But control of this new strain may be the biggest challenge of 2021.

In short, there are reasons for optimism as the vaccine rolls out, but keep doing what you’ve been doing: wear a mask (you don’t have to like it- I certainly don’t) and continue to limit social contacts. It’s the tired public health adage, but let me tell you, it works. Things will get better, and it is very likely that COVID-19 will continue to be with us for years to come, with immunity in the population transforming it gradually from a crisis to a smaller but persistent threat on a scale like seasonal flu.

I’m grateful and honored to be a part of the public health and science communities, who have poured their energy and efforts into saving lives. And to all in health care, education, essential services and others—it has been a team effort. While the circumstances are terrible, it is a positive development that the public is better informed about the importance of infectious diseases, versed in the basics of epidemiology and disease transmission dynamics. May we remember the lives lost and forever altered by this pandemic.

I wish you the best for a healthy and safe new year.


Marc Lipsitch, DPhil
Professor of Epidemiology
Director, Center for Communicable Disease Dynamics
Harvard T.H. Chan School of Public Health

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