Cold Sores Contagious? Yes, and Especially Dangerous to Newborns and Very Young Children

by on 2009/11/30

What Are Cold Sores?

Cold sores are a condition caused by infection of the herpes simplex virus (simply known as HSV), usually the type 1 strain (whereas the type 2 strain is usually responsible for genital herpes), although both strains are capable of causing either condition.

Can I Get Rid of It?

Herpes is a virus, and once you've been infected you can never get rid of it (sorry). Although, there is currently work being done on a vaccine for type 2 herpes to vaccinate women against genital herpes, and the researchers believe that this vaccine could easily be translated into a vaccine for the the type 1 strain to prevent cold sores.

Oral herpes is the most common form of herpes infection and is known as "herpes labialis", which is the infection that occurs when the virus comes into contact with oral mucosa or abraded skin.

Herpes remains in a dormant stage the majority of the time where it resides in the sensory nerve cells near the site of the initial infection (your face, in the case of cold sores), only to emerge from those cells immediately before, during, and immediately after an outbreak which usually lasts from 2 to 21 days, typically right around a week for most people. You should be aware of the fact that you're still contagious (what's called "viral shedding" is occurring) up to a week before and after your active outbreak, so it is possible that you're contagious even when you don't have a visible cold sore if you're about to get one or you just had one--when you're shedding the virus but showing no symptoms (i.e. cold sores), this is known as "asymptomatic shedding".

Cold Sores Contagious Even When I Don't Have One?

Asymptomatic shedding occurs in most individuals infected with herpes, asymptomatic shedding is typically considered the most common way in which HSV-2 genital herpes is transmitted. People assume that because they're not symptomatic that they're not contagious and therefore aren't as careful as they would be if they were symptomatic and so end up infecting people because, although they're not symptomatic, they're still shedding the virus and therefore still contagious. Also, asymptomatic shedding is more frequent in the first 12 months that a person has HSV.

Mind you, frequency of asymptomatic shedding has no correlation with frequency of symptomatic outbreaks: this means that the frequency with which you suffer visible outbreaks has no bearing on how often you are symptomatically shedding.

Preventing Spreading HSV with Anti-Viral Medication

When one partner has herpes simplex and the other does not, the use of anti-virals like acyclovir and valacyclovir by the infected person can reduce the odds of infecting their partner by up to 50%. It is believed asymptomatic HSV-2 viral shedding occurs on 10.8% of days per year in patients not undergoing antiviral treatment, versus 2.9% of days while on antiviral therapy.

Children (especially newborns) and the Danger of Herpes Infection from Someone with a Cold Sore

Although many people infected with HSV develop typical visible symptoms such as lesions and sores, the majority of those infected with HSV (both HSV-1 and HSV-2) either go undiagnosed or display no physical symptoms of infection (they're asymptomatic) and in many cases the very first symptom a person will have of their own infection is the horizontal transmission of the virus to a sexual partner or the vertical transmission of the virus from a mother to a newborn at term in the form of neonatal herpes which can be very dangerous and is often lethal to the newborn.

Your Cold Sore Could Be FATAL To A Newborn!

***Without treatment, neonatal herpes is fatal in 50% to 85% of cases and up to two thirds of the survivors have lifelong disabilities. Death and disability remain common even with treatment, partly because the infection can be difficult to recognize, so that many infants do not get treated in time.

The report estimates that at least 460 cases and perhaps as many as 2,800 cases of neonatal herpes occur each year in the United States. By contrast, congenital rubella and HIV infection, syphilis, and gonorrhea in newborns all are less common than neonatal herpes.


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