Infectious Diseases

Why won’t my doctor prescribe antibiotics for my illness?

DEAR DOCTOR K: I've been under the weather for a few days. This morning I blew my nose and saw greenish mucus, so I called my doctor and requested antibiotics. He refused. Why?

DEAR READER: Your doctor is correct not to prescribe antibiotics based on the color of your mucus alone. Despite what many people think, you cannot rely on the color or consistency of nasal discharge to distinguish viral from bacterial sinus infections. That's an important distinction because only bacterial infections respond to antibiotics.

Could you discuss the new approach to vaccines that could supposedly revolution immunization?

DEAR DOCTOR K: I heard on television about a possible new vaccine against HIV, Ebola and other terrible viruses. That sounds like very good news, or is it just hype?

DEAR READER: You may well have heard about a new approach to creating vaccines. The approach is called "passive immunization with neutralizing antibodies." It could revolutionize immunization against Ebola and other viruses, including HIV (the virus that causes AIDS) and influenza (flu) viruses.

Does my son need to get the HPV vaccine?

DEAR DOCTOR K: A friend says that my young son should get the vaccine that protects girls against cervical cancer. That doesn't seem to make sense. Can you explain?

DEAR READER: Your friend is right, and here's why. The vaccine is against a virus called human papilloma virus (HPV). There are more than 100 strains of HPV; about 40 of these strains can be transmitted by sexual contact. So-called low-risk strains cause genital warts. High-risk strains can cause cancers of the cervix, anus, penis and throat. I'll call these the HPV-related cancers. Not all of these cancers are caused only by HPV, but the virus is an important cause of each. Most cases of cervical cancer in women in the United States are caused by HPV.

Is there any new information on the link between Zika virus and birth defects?

DEAR DOCTOR K: In a recent column, you said that doctors were still conducting research to see if the Zika virus does, as feared, cause birth defects -- particularly, babies born with small heads and brains. Has there been any new information on that?

DEAR READER: There has, and it's important. The new information was summarized in articles in the New England Journal of Medicine in April.

Do products that claim to boost immunity actually work?

DEAR DOCTOR K: I guess everyone wants a strong immune system. But is there anything to the claims of products that advertise that they boost immunity?

DEAR READER: In a word, no. Our immune system does a remarkable job of protecting us from bacteria, viruses and other microbes. That's good, because they can cause disease, suffering, even death. It seems logical to want to give your immune system a boost.

Does the immune system really change with the seasons

DEAR DOCTOR K: A friend heard about a study that said a person's immune system changes with the seasons. That seems incredible to me. But if it's true, it's fascinating. Do you know what she is talking about?

DEAR READER: I think I know the study she is referring to. Before describing what it found, it's worth talking a bit about the immune system and also about genes.

What is sepsis?

DEAR DOCTOR K: My father had routine surgery. Soon after, he developed something called sepsis that almost killed him. He's OK now, but I'd like to understand what happened to him.

DEAR READER: He and you are lucky. Not everyone makes it. Sepsis is a condition in which the immune system goes awry. Think of the immune system as our personal army, with an arsenal of weapons. It is meant to protect us from foreign invaders (like germs). Unfortunately, in attacking foreign germs, it sometimes can go overboard -- and its weapons can injure us.