COLUMBUS, Ohio (WCMH) — On March 9, 2020, Gov. Mike DeWine, Lt. Gov. Jon Husted and former state health director Dr. Amy Acton appeared at a lectern in the Ohio Statehouse.

The leaders warned of an imminent threat posed by COVID-19, a mysterious respiratory illness spreading in other countries and gaining a foothold in the U.S.

“From what we see around the world and in the United States, this disease will, for a period — will, for a period — significantly disrupt our lives,” DeWine said.

That period of time reached two years on Wednesday.

In the 24 months since that news conference, the peaks and valleys of Ohio’s COVID-19 waves have marked the time and the public response. Below is a timeline:

Early 2020: Ohio shuts down, political pressure heats up

Wave: Jan. 2-June 8, 2020

Although Ohio announced its first COVID-19 cases in March, subsequent investigation by the Ohio Department of Health backdated Ohio’s earliest infections to Jan. 2.

It was in March that Ohioans got their first taste of the next two years: health system stress from a deadly disease, closed businesses, virtual schooling, mask-wearing, and more.

By the end of March, Ohio had seen more than 6,000 total cases, a scary number at the time but one the state would see daily for large chunks of the pandemic to come.

Deaths, as a proportion of cases, were at their highest level in April and May because the treatments in use for COVID-19 patients today were not yet available.

Opposite the human toll, crowds throughout the state gathered to protest mask mandates and business closures. Some of the most animated protests were outside the statehouse in April.

As cases in this early wave started to fall, DeWine and Acton began lifting restrictions from the stay-at-home order in May, starting the reopening process.

As of June 8, 2020: 42,063 cases, 6,448 hospitalizations, 2,303 deaths.

Summer 2020: Cases steady, Ohioans adjust to new normal

Slow period: June 9-Sept. 20, 2020

Summer brought Ohio a steady pace of COVID-19 infections, as daily onset cases hovered around 1,000 from late June to late September.

Relatively low cases totals gave Ohioans room to adjust to life with COVID-19 as a concern. Treatments for the virus were improving, but vaccines were still months away.

Among the highlights of summer 2020: Major League Baseball returned in July, and DeWine had a false positive coronavirus test result in August. K-12 and college students also returned to campuses in August and September.

As of Sept. 20, 2020: 150,611 cases, 14,017 hospitalizations, 4,286 deaths.

Fall/Winter 2020/2021: First major spike

Wave: Sept. 21, 2020-March 9, 2021

Lower temperatures sent people indoors, lessened social distancing and spread the virus more easily.

Cases started ticking up in late September at around 1,000 per day. They hit 2,000 by Oct. 12, then 3,000 on Oct. 23, and 4,000 on Oct. 28.

Nov. 2 brought 6,000, then Ohio saw 9,000 cases per day a week later. And a week after that, the state had its first day of 10,000 cases.

This late 2020 wave peaked at 13,374 cases on Nov. 30, and daily infections didn’t fall to 1,000 until February. As this wave subsided, however, vaccines became available and offered hope that the worst of the pandemic would be behind Ohio. It wasn’t.

As of March 9, 2021: 991,049 cases, 47,082 hospitalizations, 18,926 deaths.

Spring/Summer 2021: Cases dwindle, vaccines save lives

Slow period: March 10-June 29, 2021

Vaccines rolled out to more and more people in the spring of last year, giving the most at-risk people and then all adults the ultimate way to protect themselves from the virus.

New cases stayed around 1,000 and 2,000 per day, then they hit lows not seen since the pandemic’s earliest days. Cases dropped into the hundreds by May, bottomed out at 144 on June 27, and stayed in the hundreds through most of July.

Ohio and Columbus lifted their mask mandates, and sporting events brought back pre-pandemic crowds.

Vaccines, however, became a tough sell for some. Skepticism and misinformation on their effectiveness contributed to slowing uptake. Politics also played a divisive role, as an NBC4 Investigates analysis in July found Ohio county vaccination rates better correlated with 2020 election results than a county’s population.

DeWine’s Vax-A-Million lottery had some effect in increasing new shots by offering cash to vaccinated adults and scholarships to vaccinated students. But Ohio consistently ranked in the bottom third of U.S. vaccination rates.

As of June 29, 2021: 1,113,631 cases, 54,295 hospitalizations, 20,536 deaths.

Summer/Fall 2021: Delta

Wave: June 30-Dec. 6, 2021

Cases started to tick up ever so slightly around Independence Day, driven by a new, more contagious variant called “delta.” First discovered in India, delta wreaked havoc in Ohio and the U.S. in the fall.

Testing ramped up again, hospitals experienced a renewed level of stress, and deaths spiked. Local mask mandates came back, but the statewide order did not. Anti-mask, anti-vaccine and anti-mandate protesters continued demonstrations.

Dr. Bruce Vanderhoff, ODH’s chief medical officer, was promoted to state health director on Aug. 11.

With vaccinations now widely available, infections, hospitalizations, and deaths from COVID-19 Ohio skewed younger. Vaccination rates were better among the elderly, so middle-aged and younger people made up larger proportions of coronavirus casualties.

Cases went from the low hundreds in mid-July to more than 9,000 by early September. Then cases peaked again in mid-September, and the delta wave was slowly improving.

Daily infections got lower than 3,000 by late October, but then they rebounded to their delta wave highpoint by Thanksgiving. The worst of the pandemic was still ahead — but it wasn’t because of delta.

As of Dec. 6, 2021: 1,764,478 cases, 79,891 hospitalizations, 28,734 deaths.

Late 2021-present: Omicron

Wave: Dec. 7, 2021 through present

Delta’s destruction was short-lived, but not because it disappeared. Instead, it was replaced in December as Ohio’s dominant variant by the omicron variant, first detected in South Africa.

Ohio State University scientists sequenced Ohio’s first omicron cases on Dec. 7. What followed was an intense spike in infections far greater than anything in the nearly two years prior.

When omicron was first detected in Ohio, the state’s 7-day daily average of new cases was just over 7,000. Three weeks later, it was over 20,000. And a week after that, it stood above 24,000 for four straight days.

The omicron wave peaked on Jan. 3 and 4 with more than 32,000 cases each day. But the worst days of omicron were likely undercounts, because of unreported at-home tests and sick people who couldn’t find a test during a widespread shortage.

This highly contagious omicron, however, was less deadly than previous strains. Deaths from COVID-19 in Ohio peaked in the omicron wave at 188 on Jan. 13. Although that was one of the highest levels of the pandemic, multiple days at the end of 2021 saw more deaths despite having a fraction of cases.

An upside to omicron’s swift movement through the public was that new infections came down as quickly as they rose, and the new year brought sighs of relief.

Ohio’s 7-day daily average fell from above 24,000 cases to below 3,000 in only a month. As February rolled into March, new infections were at levels as low as summer 2021.

As of Tuesday, March 8: 2,660,728 cases, 112,951 hospitalizations (12,263 have unknown dates), 37,212 deaths.

Ohio’s endemic future

Now in March, new cases in Ohio after the omicron wave have fallen near their lowest levels recorded. The state reported just 431 on Monday, for example, and just over 6,000 total last week. Infections haven’t been this low since July 2021.

Columbus even lifted its mask mandate on Monday, as did Columbus City Schools on Tuesday.

This improvement is not proof, however, that COVID-19 will just go away, state and local health leaders have maintained. Instead, they expect the virus to become endemic — something that’s dealt with every year — like a deadlier version of the flu.

“Instead of these big peaks, there is likely to always be a baseline level of some type of infection or activity going on,” said Dr. Joseph Gostaldo, an OhioHealth infectious diseases expert, in a Feb. 4 news conference.

“And it may go up or down based on the seasons. For example, with respiratory viruses like influenza, we typically see them more in the winter months.”

A University of Washington study from February estimated 73 percent of Americans were immune to omicron through infection or vaccination.

“We have changed,” Ali Mokdad, a UW professor of health metrics sciences told the Associated Press. “We have been exposed to this virus and we know how to deal with it.”

But new variants are possible, especially since Ohio and the U.S. have not reached herd immunity with vaccinations. As of Tuesday, 61.91 percent of all Ohioans have at least one shot of a COVID-19 vaccine.

That ranks 43rd out of 50 states, according to the Centers for Disease Control and Prevention.