DEAR READER: Yesterday I talked about a new kind of immunization: passive immunization with neutralizing antibodies. This approach may be effective against many different strains of a virus. It may also allow large amounts of a vaccine to be stored, ready to nip an exploding epidemic in the bud.
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.
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.
DEAR READERS: In yesterday's column, I discussed new evidence that the Zika virus probably causes a brain birth defect that leads to small heads and brains (microcephaly). This can occur when a pregnant woman is infected early in pregnancy, when the baby's brain is developing.
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.
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.
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.
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.
DEAR READER: In yesterday's column, I answered questions about the Zika virus. Today, I'd like to answer several more, and also talk about how we can protect ourselves against this and other epidemics.
DEAR READERS: Not surprisingly, we've been getting lots of letters about the Zika virus. In today's column, I'd like to answer the questions that many readers are asking.