Back in March, Major League Baseball informed teams that those who reach an 85 percent vaccination rate among "tier 1" personnel -- players, coaches, trainers -- would face looser COVID-19 restrictions as it pertained to masks, tests, and social activities like dining out together. The promise of returning to normalcy has reportedly led to about 15 teams reaching the 85 percent threshold. The Chicago Cubs are not one, and according to team president Jed Hoyer, it doesn't appear that they'll be hitting that mark anytime soon.

"It's disappointing to not be at 85 percent as a team," Hoyer said on Thursday, according to ESPN's Jesse Rogers. "We've worked hard to try and convince or educate the people that have been reluctant. We're at a place right now -- I'm not going to give up hope we're going to get there -- my level of optimism is waning. It is disappointing."

It's unclear how far away the Cubs are from the 85 percent mark. It's also unclear why the individuals who have not been vaccinated are holding firm to that decision. 

Hoyer's efforts to sell his players on getting vaccinated have even involved him describing it as a "competitive advantage," since a high vaccination rate prevents outbreaks, which can in turn decimate a roster. Not everyone in Chicago's clubhouse seems to buy that thinking.

"I don't necessarily see that as a competitive advantage or disadvantage," right-handed Jake Arrieta said. "We have a lot of guys vaccinated. We have not had any cases in the past month, so we're doing OK as a group. And we're being careful about where we go and who we're around."

The Cubs were the only team to go without a positive COVID-19 case among players during the 2020 season, but crediting that accomplishment to precaution without considering the role luck plays in highly infectious diseases is a mistake. To wit, the Cubs placed three relievers on the COVID-19 injured list in April after a number of coaches tested positive.

The COVID-19 vaccinations minimize the risk of a similar incident heading forward. According to Yale Medicine, the Pfizer and Moderna vaccinations were each around 95 percent effective in preventing symptomatic infection in clinical trials. The Johnson and Johnson vaccine, popular among ballplayers given that it requires just one dose, was found to be 72 percent effective (though it was tested at a time when more variants were in circulation). 

The New York Yankees, who recently had a number of vaccinated individuals test positive, received the Johnson and Johnson shot.  Arrieta's hesitancy toward getting vaccinated appears inspired in part by the Yankees' ghost outbreak, as he told NBC Chicago: "Based on that information and the science, the people that are vaccinated shouldn't necessarily have to worry about getting COVID-19, but that has also been proved wrong as well."

Arrieta is mistaken about the science. Zach Binney, an epidemiologist, recently explained on Twitter why the Yankees' outbreak is evidence of the vaccinations' effectiveness. Additionally, only one of the nine Yankees who tested positive had any symptoms, and those were mild and ceased after a day. COVID-19 has resulted in more than 584,000 deaths in the United States alone, according to the CDC.