People of my generation can tell you where they were when they heard that President Kennedy had been shot. Nearly all Americans over the age of 30 remember what they were doing when they heard that the World Trade Center had been attacked on 9/11.

Such is the way shared community trauma affects us. Although the impact of the coronavirus — and the disease it causes— was something that developed over a series of months, everyone I know can tell you when they realized that the world had catastrophically changed due to Covid-19’s arrival in the US.

Last March 10, when Gov. Baker declared a state of emergency for Massachusetts, there were 696 cases of Covid and 25 deaths in the US, a large number of them in Washington State. Massachusetts had 91 cases and zero deaths, and most of us didn’t think it would touch us, let alone upend our lives.

As of this writing, the United States has now experienced 29 million documented cases and more than 522,000 deaths from Covid-19. Massachusetts has had 560,000 cases and 16,000 deaths.

As a person who has spent most of my life in public health, my antenna certainly went up when I read about a respiratory virus in Wuhan, China, at the end of December 2019. Though I was aware of the potential of these viruses from the world’s experience with H1N1, the Avian flu, SARS 1, Swine flu, Ebola, Legionnaires’ Disease, etc., the United States was mostly spared from the worst of those viruses, which wreaked havoc in other countries.

At the time, I was more upset by the blame heaped on the Chinese and Chinese Americans and made sure that we took my son out for his birthday dinner to a Chinese restaurant to show our support for that community. We were the only non-Asians in the restaurant.

In January 2020, I was at UMass Boston to meet Marcelo Suarez-Orozco, then a finalist for the chancellor position at UMB. That very day a student was diagnosed with Covid at the student health office. It was the first case of the coronavirus in the eastern US and only the eighth case in the entire nation. It was scary to think I was there, but officials assured us that our risk was low.

In February, I went about my regular business, although the media reported ominous stories on what was called “community spread” of the virus, meaning that health officials couldn’t trace a positive Covid case to a particular individual — it just appeared.

Haley House in Roxbury had the misfortune of reopening on Feb. 1 and my wife and I went to a crowded fundraiser in New York City on Feb. 3, oblivious to the fact that the virus was sweeping into that city. South End art openings, birthday parties, a community college conference in Washington DC, fundraisers, civic meetings — all the normal things continued.

Yet, while President Trump was saying everything was under control, the virus was stealthily and steadily moving into the country.

On Feb. 26, the now-notorious Biogen conference opened at the Boston Marriott Long Wharf hotel, an event that ultimately caused the infection of as many as 330,000 people and defined what became known as a “superspreader event.”

Any hope of avoiding the impact of the coronavirus disappeared in March. In 12 short days, our world turned upside down. Even as cases and deaths mounted worldwide and nationally, the month started normally. I went to a political fundraiser on March 1. The presidential primary was held on March 2. On March 4, my band, the Savin Hillbillies, played a fundraiser for the Uphams Corner Health Center at Dorchester Brewing Company.

There was a celebration of Dr. Suarez-Orozco at the UMass Club on the 6th. I went to Mass at St. Cecilia’s Church in the Back Bay on March 8. It was our last in-person Mass with Fr. John Unni, who now attracts thousands of congregants online.

I took the subway to several meetings on Monday, March 9, the day Italy went into lockdown. Massachusetts declared a state of emergency on the 10th. Events were being canceled in droves, but the Irish Cultural Centre decided to go forward with its event at the BC Club the night of the 10th. I remember going and leaving very early, as I felt uncomfortable even being in an elevator. It was my last subway ride home.

On the 11th, the day the World Health Organization declared a pandemic,I rode my bicycle downtown for meetings. On the 12th, I pedaled to BNN for an interview about the coronavirus with Chris Lovett.

My interview with Chris was prescient. I railed against the federal government’s inability to provide tests, saying “We don’t have enough test kits to screen people. As a result, it’s spreading through the community through asymptomatic people who are walking around the community and have the virus and are spreading it to other people, many of whom could be in grave danger because of this.”

I laid out the conditions we were seeing that would lead to the horror show that Covid has brought to the US and to the world. After the interview, I rode my bike home, and began my year of social distance, masking, and creating an impenetrable bubble. A couple of weeks later, I co-authored an op-ed in the New York Times calling for an immediate national policy for the wearing of masks in public.

The shame of this was how government wasted the time from New Year’s Day to the lockdown. The Obama administration had left the Trump administration a 69-page document entitled, “Playbook for Early Response to High-Consequence Emerging Infectious Disease Threats and Biological Incidents” that detailed what to do. Covid-19 should not have been a surprise and authorities knew the things that have worked in the past to suppress transmissible diseases.

We did not have the necessities to manage the virus, such as Personal Protective Equipment, screening tests, and mandating the use of masks. It took way too long for our national and state and city governments to come along to these tried-and-true initiatives. Some officials never adopted these common sense things. The result is the disaster that Covid has been for our country.

A year ago, we had the chance to slow down and manage the virus. Instead, we got denial, obfuscation, and homicidal actions that resulted in trauma for millions of our country’s families. These wounds will take years to overcome.

This isn’t our first pandemic and it certainly won’t be our last. For the sake of future generations, let’s hope we have learned something useful from our experience with Covid-19.

Bill Walczak is a Dorchester resident and co-founder and former CEO of Codman Square Health Center.