I would like to address concerns outlined in "I am vaccine hesitant, and here's why ..." (Aug. 5).

Protecting the vulnerable and keeping the health care system running are only part of the strategy. The real goal was to protect everybody, keeping in mind the very real costs of hard interventions like lockdown.

Both masking and vaccination are ways to avoid the lockdowns that are introduced when the system is failing. They also efficiently protect the vulnerable in ways that the alternative (shielding) does not. Those who are most vulnerable require full-time care. It was never feasible or ethical to isolate these people and their caregivers from society.

Vaccines and masking remain two excellent ways to avoid lockdown and collapse of health care systems. The fact that some people in society are opposed to both mask use and vaccination is a challenge.

For these people, I would just ask if they know people who have battled cancer or are immunocompromised or simply very old. Caring about these people means providing an environment where they do not have challenges in addition to the ones they already face.

"Herd immunity," or community immunity, is also a concept that is frequently misunderstood and misused. First, diseases are not fully controlled by natural immunity. For example, measles is still a risk precisely because natural immunity doesn't extend to children and vaccination levels are not sufficiently high.

Moreover, when we talk about levels of immunization needed to prevent outbreaks, we need to consider those who cannot be or have not been immunized, and those who do not develop a sufficient immune response. If vaccination coverage, or community immunity, is not high enough we put these people at risk.

Finally, there is generally no hard threshold. Higher levels of immunity are better. Each person vaccinated is a potential chain of infection that is interrupted. This means that the number and coverage of restrictions necessary to control an outbreak is lower.

Questions about the efficacy and side-effects of vaccines are merited. Since vaccines are both widely used and given to otherwise healthy individuals it is especially critical to evaluate the risk/benefit profile. Vaccines must go through additional testing and mandatory reporting of serious adverse outcomes that is not done for other pharmaceuticals, to identify those which are related to the administration of the vaccine itself.

Notably this system also identifies deaths that are unrelated to the vaccine as many of the first vaccinated were frail elderly. Thus far the rate of serious events has been remarkably low considering the number of vaccinations given, and concerning rare events have been reported to the public.

Evidence on comparative effectiveness would come from trials comparing vaccines. The information would certainly be nice to have, but not necessary to weigh the risk/benefit of any given vaccine. We are blessed with a choice of very effective vaccines.

Lastly, we don't know long-term effectiveness or harms from vaccines. In the bigger picture we also don't know long-term anything about COVID infection. The impact of viral infection could linger with possible long-standing impact on major organs and body function.

Lisa Langsetmo is a senior research fellow in epidemiology and community health at the University of Minnesota. The views expressed here are solely her own.