Charts: See how vaccinations are protecting older people and driving down Mass. coronavirus numbers

A coronavirus vaccine being prepared at a clinic in March at the Prince Hall Grand Lodge in DorchesterLane Turner/Globe Staff

From the moment COVID-19 arrived in Massachusetts, the disease took the harshest toll on the state’s oldest residents. Now, a decline in the most severe cases among older residents is helping to drive the state’s comeback from the pandemic.

Cases, hospitalizations, and deaths among the state’s oldest age groups have dropped notably since the second coronavirus surge peaked early this year, as widespread vaccine efforts set in across the state.

“The vaccines are doing exactly what we hoped – bringing deaths and hospitalizations down, and also cases,” said Dr. Paul Sax, clinical director of the Division of Infectious Diseases at Brigham and Women’s Hospital.

The charts below, drawn from state coronavirus data, tell the story.

First, let’s look at hospitalizations.

The number of older people among those hospitalized ballooned during the second surge, but has shrunk significantly since then.

Hospitalizations of people 80 and older, the largest group, for example, fell from a two-week total of 206 reported on Jan. 13 to 24 on April 28. That’s an 88 percent decline.

The declines generally get smaller the younger the age group.

Now, let’s look at deaths. A similar pattern emerges in the age breakdown of people who have died from the coronavirus.

The number of people 80 and older among those who died fell from a two-week total of 560 on Jan. 13 (and again on Jan. 27) to 24 on April 28. That’s a nearly 96 percent decline.

Again, the declines generally get smaller the younger the age group.

Sax said in an e-mail it was “exciting how [the data] show the steep decline in deaths among by far the most vulnerable group – those over 70 and 80.”

Here’s a different stat that reflects the declining numbers of older people among those who have died: The average age of people who have died has declined to 69 from as high as 81 as recently as the start of the year (and even higher last year).

Dr. Howard Koh, a professor at Harvard T.H. Chan School of Public Health and a former US assistant health secretary and Massachusetts public health commissioner, said in an e-mail that “vaccination has clearly triggered dramatic drops in death and disease for older people prioritized in immunization strategies. These trends demonstrate — in a stunning way — the life-saving power of prevention and public health.”

Now, let’s look at cases.

Young people are by far the leaders in the number of cases, though they are less likely to get sick or die from the virus.

While every age group has seen cases drop from the winter surge, older groups have outpaced younger groups in percentage decline. The two-week tally of cases among the 80-plus group declined 92 percent from Jan. 13 to April 28, for example. Meanwhile, cases among people 0 to 19 declined 59 percent from their peak on Jan. 20 to April 28.

Note that the chart also shows that the oldest groups of people did not see the pronounced March “bump” in cases that the younger groups did.

Samuel Scarpino, an epidemiologist at Northeastern University, said the lack of that bump among the oldest groups, who were prioritized early to get the vaccines, showed the vaccines had kicked in — and warded off a surge caused by the arrival of the B.1.1.7 variant.

Urging everyone in Massachusetts to get vaccinated, Governor Charlie Baker said last week there was “overwhelming evidence at this point, based on many of the populations that have been vaccinated so far, which includes a lot of very vulnerable populations, that vaccines work.”

The US Centers for Disease Control and Prevention also recently said real-world results confirm clinical trial data, issuing a study that found the vaccines cut hospitalizations 94 percent among people 65 and older.

Scarpino noted that people in older age groups have been protected not only by being vaccinated themselves but by the early vaccination of health care workers and caregivers.

“We were headed in the direction of India and avoided it only because of the incredible vaccination campaigns in the US,” he said.

He said the protective effect of vaccinations is already spreading to younger age groups, which is why the March bump in total Massachusetts cases has “turned over so fast.”

Looking ahead, Sax cautioned that more people still need to be vaccinated to make progress in the state’s battle against the virus. “The highest risk for getting COVID has always been teens and young adults, and now we just need to focus on getting them fully vaccinated,” he said.

Travis Andersen of the Globe staff contributed to this report.