Natural COVID immunity does not outshine vaccination benefits
DEAR DR. ROACH: I am told by doctors that the natural immunity your body develops by having had the COVID-19-19 virus is just as, or even more, effective at protecting you as one of the three vaccines that you are pushing people to get. Like I've read up on, natural immunity is science also. Will you please confirm or deny that statement? -- J.B.D.
ANSWER: There remains controversy about the relative benefits of the immunity gained from a vaccine versus the immunity gained by surviving a case of COVID-19. What is clear, however, is that not everybody who survives a case of COVID-19 has long-lasting immunity, and they are susceptible to getting another case.
In the original study on the Pfizer vaccine, those who had a history of COVID-19 infection had as much benefit from the vaccine as those who had no history of infection. For this reason, I still recommend vaccination, even for those with a history of COVID-19. A study from Yale published in October found that immunity can wear off as soon as three months after infection.
Vaccines are particularly important as new variants are introduced. Natural immunity after a bout with one variant of COVID-19 may not provide protection against other variants. The vaccines provide better (though still not perfect) protection against many of the variants currently circulating. There have been documented cases of people getting COVID-19-19 despite vaccination, just as there are in people who have already had COVID-19-19.
What is more important is that vaccines provide high-level protection, which most (but not all) studies find to be as good as, or superior to, the protection after a case of COVID-19. But you can get that protection without the risk of death and long-term complications of getting a "natural" case of COVID-19. While it is true that "only" 1.8% of people die from their COVID-19 infection, that still means more than 700,000 confirmed deaths in the U.S. alone. At least 30% of survivors of COVID-19 infection will have persistent symptoms three months after infection. In terms of safety and effectiveness, there is no comparison whatsoever between getting COVID-19 and getting the vaccine: The vaccine is a much better option.
DEAR DR. ROACH: If I must urinate very badly, it often seems that I get the urge to go again just a short while after voiding. It's very annoying. Why is this happening? -- M.E.
ANSWER: The bladder wall is mostly made of muscle fibers that contract to initiate urination. If these muscles get stretched more than they should (to the point where the bladder sends pain signals to the brain), they cannot contract properly for a while -- so you cannot empty the bladder completely and will get the sensation to void again in a shorter period of time than you expect. It's not good to wait so long to void. Over time, it may cause damage to the kidneys.
If you have had a whole lot of fluid, and the kidney is making a large volume of urine, naturally you are going to need to void more frequently, even if you didn't overstretch the bladder.
DEAR DR. ROACH: Does lactose-free milk have calcium? -- T.S.E.
ANSWER: Yes, lactose-free milk has calcium. Generally, lactose-free milk is made by adding the enzyme lactase to regular milk, which breaks down the milk sugar lactose into its two component sugars, glucose and galactose. This makes the milk taste sweeter, but does not affect the calcium.
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.
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