Published November 8, 2021
Iodine seems to be the newest alleged remedy for COVID-19. Anti-vaxxers are using iodine solutions to gargle, spray up their noses, and even swallow as a way to prevent COVID infections. This is predominantly based on a YouTube video from an emergency room doctor in Thailand that went viral on Facebook and Twitter.
While some iodine is necessary in development and bodily functions, taking too much can result in significant medical problems. Fetuses and infants need some iodine for bone and neurologic development, and iodine is a necessary part of thyroid gland function. Complications can result from excessive iodine, especially from ingesting over-the-counter povidone-Iodine solutions such as betadine used to treat mild cuts and scrapes on the skin. The most common complications are related to the thyroid gland including goiter, hypothyroidism, thyroiditis, and thyroid papillary cancer. Acute poisoning can result in burning of the mouth, throat, and stomach, fever, pulmonary irritation and shortness of breath, abdominal pain, nausea, vomiting, diarrhea, weak pulse, kidney damage, neurologic changes, and/or coma.
Like ivermectin and hydroxychloroquine before it, there is no compelling evidence that iodine provides any benefit for preventing or treating COVID-19. Any assertions to its effectiveness comes from poorly done studies, studies not done in people, and studies not done with the novel coronavirus. In the case of iodine, some of the basis for its use is mere speculation based on the properties of iodine or studies done with bacteria or other viruses.
Only In Vivo Studies In Humans Matter
The most important aspect of any medical study or trial is that the results only apply to people when they are done on humans. While evidence from in vitro (test tube, culture dish, or other medium outside a living organism) and in vivo (within the living) animal studies can provide clues to the possible effectiveness of a medication, it is vital to not make any decisions about using the medication in people based on these types of studies. The same is true of any studies not specific to COVID-19.
There have been numerous studies that hint at iodine being effective for viruses, but most are quite a stretch to effectiveness to prevent or treat COVID in people. For example, a 2011 study using respiratory cell cultures showed that substituting iodide in a respiratory mucosal protein could boost immunity and inactivate adenoviruses and respiratory syncytial viruses. This led to a 2014 study in newborn lambs showing that injection of potassium iodide reduced the number of respiratory syncytial viruses in their respiratory system. Somehow this led to a letter to the editor in November 2020 suggesting that iodine could be a “magic bullet” to treat and prevent COVID-19, despite the fact that a coronavirus — especially SARS-CoV-2 — has never been tested.
Although there have been some studies done in people that show povidone-iodine can inactivate coronavirus in the mouth, the effect does not last long enough to stop coronavirus infection or reduce the severity of the disease in those already infected.
Quality Studies Are Essential
Aside from being tested in humans, before any medication can be used in people there has to be convincing evidence that it is safe and effective. This comes down to the type and quality of study done, which is a very complicated topic. For those who are able to evaluate the quality of medical studies, it is clear that the studies indicating that iodine is effective provide low-quality evidence or are poorly done. There are no studies of acceptable quality studying iodine’s effectiveness.
The lowest quality evidence for human studies try to draw conclusions based on looking at an individual person (case study) or a small group of people (case series). For example, the “magic bullet” conclusion was also based on a study showing that Mandl’s paint (composed of 1.25% iodine and 2.5% potassium iodide in peppermint oil and 90% alcohol in glycerin) may have prevented some people from getting the H2N2 influenza virus during the 1957-1958 flu pandemic and an undocumented assertion that Japanese people have less COVID-19 due to higher quantities of iodine in their diet.
The highest quality evidence comes from randomized placebo controlled trials, but there have been none studying iodine for prevention or treatment of COVID-19 in people.
All Risk with No Benefit
Infectious disease experts, other healthcare providers, and even the manufacturers of betadine are warning people not to ingest, spray, or gargle iodine as a prevention or treatment for COVID-19. It is not surprising since there is no reliable evidence to prove any benefit and many known complications.
What has been shown to be of significant benefit are the COVID vaccines, which are highly recommended by public health agencies, infectious disease experts, and other healthcare providers. Believing one physician/news networks/YouTube videos over the recommendations of the entire public health community and the overwhelming success of the vaccine seems extreme to all but the most indoctrinated anti-vaxxers.
The NeedyMeds website has a database of over 100 nationwide resources for those who have been impacted by COVID-19. For those looking for information on receiving a coronavirus vaccine, all adults and children over 12 years old can receive the vaccine free of charge. There may be options for children ages 12-18 to get vaccinated even if their parents don’t grant permission. Search online for your state’s requirements, area’s locations, and appointment availability.