Tag Archives: Viral Infections

Viral Infections: The Risks And Causes Of Shingles

Shingles is a viral infection that causes a painful rash. Although shingles can occur anywhere on your body, it most often appears as a single stripe of blisters that wraps around either the left or the right side of your torso.

Shingles is caused by the varicella-zoster virus — the same virus that causes chickenpox. After you’ve had chickenpox, the virus lies inactive in nerve tissue near your spinal cord and brain. Years later, the virus may reactivate as shingles.

Shingles isn’t a life-threatening condition, but it can be very painful. Vaccines can help reduce the risk of shingles. Early treatment can help shorten a shingles infection and lessen the chance of complications. The most common complication is postherpetic neuralgia, which causes shingles pain for a long time after your blisters have cleared.

The IGA Immune System And Nasal Immunization

The IGA immune system comprises approximately 2/3 of all the immune cells in the body. Intestinal tract, respiratory tract, and skin are all exterior surfaces and are required to hold the environments’ many pathogens at bay.

IGA is one of several classes of immunoglobulins, the others being Gamma M, Gamma E, and several sub classes of Gamma G. They each have different structures and functions, but all have the basic underlying mechanisms of antigen presentation, clonal expansion, heavy chain and light chain dimers and specificity.

Mucosal gamma A occurs in pairs, with a junctional J chain and a secretory piece; The latter serves as a type of receptor on the cell surface; Imagine millions of gamma A combining sites waving on the surface of respiratory and intestinal epithelium waiting for pathogens to come along. Once combined with the virus or bacterium, they are shed into the mucus and eliminated before the virus can get to the mucosal cells.

With an IM injection of COVID-19 vaccine, all of the immunoglobulin classes except for Gamma E respond, with the earliest anybody at four or five days and peaking at 11 to 12 days. Gamma A  in the serum occurs as a single antibody, as opposed to the secretory IGA which occur in pairs. Gamma G and M reside in the serum, and do not occur in any significant amounts in the mucus, leaving  secretory gamma A alone to directly face the outside world.

Nasal immunization should theoretically be the route of choice for respiratory viruses. There is a vigorous response not only in the production of mucosal secretory IGA, but also in the production of serum immunoglobulins including IgG. However, the Titanic of medical practice turns very slowly. Part of the problem is probably tradition; immunizations have always been given by subcutaneous or intramuscular injection.

When a substance is injected, you know that it’s in the body in a precise amount, the tissues are very vascular, and the pick up rate is known, and it works well. With IM immunizations, people may get sick, because the lining membranes are not protected, but the immunized person rapidly produces huge amounts of IgG which usually keeps the infection under control. Covid is unique in its ability to evade the innate immune system, and multiply rapidly before the humoral immune response is adequate. Also, Covid  Immunity wanes rapidly, aided by the fact that Covid is always changing it’s outer form.

There are more than a dozen nasal Covid vaccines being investigated, and the early studies on hamsters and mice showed a robust mucosal antibody production as well as a serum IgG production at least as great as intramuscular injection.

There are, however, several problems. An attenuated, live COVID-19 vaccine would theoretically be the best, since the virus itself is able to get into the cells and start replicating. However, lack of experience makes the medical profession fearful. There are a huge number of “do not give to” warnings on the only currently approved nasal vaccine, which is an attenuated influenza virus. There are worries about immunodeficient people, older people, pregnant people and about the possibility that the attenuated virus will go into the central nervous system via the olfactory system.

There are practical concerns as well. Viral vector vaccines may stimulate an amnestic response to the vector that excludes the vaccine from entering the cells. The nasal vaccine might be swept away with the mucus. How much is the vaccine will remain in the nasal tissues? Will patients have any confidence in the vaccine since it’s just a spray in the nose? Will it be abused, since literally anybody could administer the nasal vaccine.

The bottom line is that of the many vaccines in trial, not a single one is expected to be approved until the early fall. Interestingly, Pfizer is working with an mRNA nasal vaccine. DNA nasal vaccines are also being tried, since DNA is a more stable molecule. A number of adenoviral vectored vaccines are in trials.

The nasal route for immunization is so promising that I believe we will eventually have nasal vaccines, hopefully tailored for current viral variants.

Nasal antibody administration, or a small molecule drug that will combine with Covid are being looked at, but since they do not produce more than transient effects, I doubt if they will be very popular. Carrageenan is an approved substance that ties up viruses, and might have a chance to succeed as a nasal spray treatment.

Pills are so much for more familiar to people as a treatment device, and seem more attractive to drug companies. I do not believe that nasal sprays will replace them as the staple of outpatient medical treatment.

—Dr. C.

Diagnosis: The Causes Of Fever Of Unknown Origin

Fever is just one of the number of symptoms that accompany most infections such as Covid and  influenza. When doctors can’t find a diagnosis for the fever, and it lasts for a few weeks, however, it is called fever of unknown origin, or FUO.

There are a bewildering number of illnesses that produce fever, and the mixture of these illnesses is different depending on geographic location, the type of hospital, and socioeconomic conditions.

Just like weight loss of unknown origin, or abdominal discomfort of unknown origin, fever without obvious cause is quite possibly be due to cancer in affluent America, and if you go in early you might have better outcomes with your treatment.

Fever has been known since earliest times, and was often considered a diagnosis on its own. In the past, the great majority of the fevers were infectious, and the outcome grave. In the mid 20th century, when I went to medical school, fevers were still mostly infectious. Antibiotics were the magic bullet, and were unfortunately overused. In underdeveloped countries, infections are still the most common cause, but in the developed world difficult to treat viral infections, autoimmune conditions, and cancer have been gaining in prominence.

When fever becomes excessive, and medication is needed, NSAIDS may be used, and works better on fever from infection than on fever from cancer. The take-home message for me is that if you use Naprosyn for a persistent fever, and isn’t effective, you might notify the doctor.

The motivation for me writing this article came from a very good posting in the New England Journal of medicine. They used a little humor, stating that modern FUO might be called “fever of too many origins”, what with all the indwelling catheters, implanted medical devices, shunts and long hospital stays. There is a separate category made for fever acquired in the hospital.

In people with AIDS, the evaluation is different depending on whether or not they are on treatment.

Tuberculosis is still a very common cause of fever.

Drugs are becoming increasingly responsible for troublesome fevers. In the early days of antibacterial therapy, sulfa  was the only drug available, frequently caused fever.  Now, sulfa is less used, and the penicillin derivatives are more common causes of fever.

If you have a fever, and have been traveling recently, be sure to tell the doctor. Your fever might be due to a tropical parasite such as malaria, particularly if you’ve been to West Africa.

Fever is an evolutionarily conserved body defense reaction and helps a person recover from an infection. The normal body temperature cycles according to the time of day; it is lowest first thing in the morning, and is higher later in the afternoon. The average body temperature used to be 37°C, or 98.6 F., but has been declining in recent decades, and is now about 36.5°C or 97.6°F. The use of electronic thermometers has cut down the amount of time needed to assess the body temperature, but added variability. I still prefer the old-fashioned thermometer.

Taking your temperature by whatever means you have available still remains a good idea when you don’t feel well.

—Dr. C.