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.