PHILADELPHIA — On March 1, Massachusetts Gov. Charlie Baker told residents in the town of Mattapan that when it comes to the various COVID-19 vaccines, “These are all very effective. People don’t need to pick one from another. People should get vaccinated. If you have a chance to get a vaccine, you should take it, whatever it is.”

The governor’s sweeping statement seems to imply, first, that everybody should get a COVID-19 shot, and second, that it’s not necessary to distinguish among the different vaccines currently on the market, like Moderna, Pfizer, Johnson & Johnson and eventually others.

Such a perspective fails to acknowledge the important factors that are part of deciding whether to receive a particular COVID-19 vaccine or any other vaccine.

When new or experimental treatments become available, including novel vaccines, and we have limited knowledge of their side effects, adverse events, efficacy, and long-term consequences, it’s important to realize that such treatments are never morally obligatory for an individual, nor for a whole population. Achieving herd immunity, while clearly an important goal, in no way demands that everyone must be immunized.

For those individuals who are young and in good health, for example, and with no comorbidities, the risk of adverse outcomes from a COVID-19 infection, statistically speaking, are very low, on a par with the generally low risks of being vaccinated. They may reasonably, therefore, decide to decline receiving an inoculation.

For those, meanwhile, who are more vulnerable to the coronavirus and its potentially damaging effects, like those who are obese, elderly, diabetic, or facing other comorbidities, it makes sense for them to consider the potentially safer path of vaccination, rather than risking a harmful (or deadly) encounter with the virus itself. Each person must make a careful determination about whether a COVID-19 vaccination is appropriate for his or her set of circumstances.

This is no different from making decisions about other vaccines like the shingles vaccine or the annual flu shot. When people get older, their chance of getting shingles, for example, increases and the CDC recommends the shingles vaccine for those over 50. Similar to COVID-19, the older you are, the greater the risk, and the greater the need to consider the possibility of vaccination to avoid the painful effects of shingles.

But it is not mandatory that everyone should take the shingles vaccine — or the flu shot or the COVID-19 vaccine — because not everyone faces the same risks or would benefit from it to the same degree.

When deciding which vaccine to receive from among the FDA-approved COVID-19 vaccines, some may be considerably more effective than others, and some may incur side effects for certain individuals.

For example, a compound called polyethylene glycol (PEG) has been identified as a possible trigger for rare allergic or anaphylactic reactions in some vaccine recipients, even in trace amounts. According to FDA documents, both the Pfizer and Moderna vaccines contain PEG, while the Johnson and Johnson vaccine does not. Thus, individuals with a PEG allergy effectively have only a single choice among the three emergency-use authorized vaccines in the US.

Another distinction among vaccines from Pfizer, Moderna, and Johnson & Johnson is their association with cell lines that were originally derived from human abortions. The Pfizer and Moderna vaccines are not directly produced or manufactured by relying on these abortion-related cell lines while the Johnson & Johnson vaccine is directly grown in such cells. All three vaccine manufacturers, however, have carried out ancillary or side-testing procedures using these cell lines.

Using abortion-derived cell lines in scientific research and industrial development raises significant ethical concerns.

When several vaccine candidates are available that are equally safe and effective, Catholics may discern in conscience the need to receive a candidate that is not associated at all, or more distantly associated, with abortion-derived cell lines. People at relatively low risk may also decide to wait for a vaccine with no connection to abortion if one is not yet available. They can make these choices as matters of conscience to avoid entanglements with the morally unacceptable practice of abortion. All of us have a right to vaccines with no connection to these cell lines. Nonetheless, the church also reminds us that we are permitted to take, under protest, any of the currently available vaccines, even those most directly associated with cell lines from abortions, if we discern in conscience that there is a serious or proportionate reason to do so. We need to give each of these options real prayerful and thoughtful discernment.

Taken together, these considerations show us how it is important not to gloss over the distinctions among various COVID-19 vaccines and imply, as Gov. Baker does, that everybody should get the first version that is available.

Rather, each of us needs to make careful decisions about our own health while also making conscientious choices in the light of legitimate moral concerns.

Fr. Pacholczyk earned his doctorate in neuroscience from Yale and did post-doctoral work at Harvard. He is a priest of the diocese of Fall River, Massachusetts, and serves as director of education at The National Catholic Bioethics Center in Philadelphia.