DEAR DR. ROACH: I read your column on vaccinations and was bothered about one issue that has not been addressed. Who are “anti-vaxxers” — those who oppose scheduled vaccinations — putting at risk by not having their kids vaccinated? Primarily others of like minds, it seems to me. Those who are vaccinated are not at risk, right? The only others I think might be at risk are future generations if we could ever fully eradicate such diseases, but that is a small probability.

I generally support people’s right to deny entering programs they disagree with, even if they are ignorant conclusions.

— T.R.

ANSWER: You would be correct if vaccines were 100% effective and if everyone could get them, but neither of those are true.

Two doses of measles vaccine are about 99% effective, but that still means that with widespread measles transmission, one person in a hundred could still get measles even if vaccinated. The reason that hasn’t happened in the past few decades is that there has been enough vaccine coverage that there has not been widespread transmission, so even people who are potentially susceptible are never exposed. This is called herd immunity, and is the major reason that people seldom die from measles now.

The success of vaccines has led to a situation where people no longer know how serious measles can be. Once vaccine coverage drops below 95% or so, then sporadic cases and even ongoing transmission are possible, a sorry state of events that we are seeing now in several communities.

Unfortunately, some children and adults are unable to be vaccinated due to underlying immune deficiency, illness or chemotherapy. These people are at extreme risk of death from measles, and the ONLY way to protect them is through herd immunity. I believe there is a moral obligation to get vaccinated for a person who lives in society to protect others.

Since people are infectious with measles before it can be diagnosed, a person’s right not to get immunized is outweighed by the cost to others who could be exposed, at least during an outbreak of measles. This is why public health officials hare able to quarantine people who are not vaccinated and potentially infectious, and on rare occasions, to forcibly vaccinate them.

Even if a person has the right to decide against immunizations, I still feel personally obligated to try to convince them that the risk of the disease, even though this is currently small, greatly outweighs the risks of the vaccine, which are negligible, even if not zero.

DEAR DR. ROACH: I recently had a cancer growth removed from my upper arm by a dermatologist. I was instructed to use Vaseline on the wound. I told them I use an antibiotic with pain reliever. I was told that because this is an antibiotic, I will become immune to the usage. Does the topical antibiotic have the same effect as a pill or shot? Because it is on the outside of my body, in different areas, will I become immune as described, or is it safe to use as I have done for 40 years?

— W.B.

ANSWER: I agree with your dermatologist. Petrolatum, such as Vaseline, is effective at keeping a wound moist, which promotes healing, and acts as a barrier to keep out dirt and bacteria.
Topical antibiotics may have additional usefulness in areas of skin infection or to reduce carriage of a dangerous bacteria like MRSA, but is no better than petrolatum for a clean surgical wound. Potential downsides to topical antibiotics include not only resistance, but also skin reactions. Accordingly, they should be used sparingly and only for clear indications.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.