When is a cold sore healed enough to kiss?

There is never a time when it is safe to kiss someone whilst you have cold sores.


Cold sores can be painful and embarassing.  At times, it may feel like you’re the only person suffering from this condition, when in fact, the white blisters surrounding your lips are incredibly common.

Also known as ‘herpes labialis’, cold sores are caused by the herpes simplex virus (HSV). There are two types of HSV – HSV-1 and HSV-2. Both can cause cold sores, but HSV-2 is spread via contact with the genitals, so you’d have to indulge in oral sex to be infected.

A cold sore (or fever blister) outbreak will usually result in small white sores forming on or surrounding your lips. These typically heal within 2 weeks.

Cold sores are highly contagious, and you should not kiss another person until blisters have healed completely. You should also abstain from oral sex.

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How do cold sores spread?

Approximately half the people in the world are carriers of HSV-1. Some of them may never notice any signs or develop any blisters, while others may have outbreaks multiple times a year.


Herpes simplex is spread via touching of the skin and contact with bodily fluids such as saliva (but also genital fluids in the case of HSV-2). That means you could contract HSV-1 by:


  • Kissing someone
  • Sharing a toothbrush
  • Sharing cutlery
  • Using the same towel
  • Oral sex


You should always avoid kissing someone with a cold sore because they are most contagious during an outbreak.


When are cold sores contagious?

Cold sores are contagious during all stages of their development and healing process. That means you could easily spread HSV-1 during times when you have active sores.


Importantly, HSV-1 can be infectious at all times, whether you have a cold sore or not. But you will be most contagious when blisters are present.


You should wait 3 to 4 days after your sores have disappeared before kissing someone.


I kissed someone with a cold sore. What should I do?

Don’t panic. Given that half the world population has HSV-1, there’s a good chance you do too.


The most important thing you can do is to monitor for any breakouts. There is no way of knowing whether you will definitely get a cold sore if you kissed someone who has one. Your immune system may be strong enough to fight a flare-up.


If you notice redness or pain developing around your lips, take an antiviral medication such as acyclovir, famciclovir or valacyclovir immediately. When treated early (within 48 hours of development), cold sores will heal much quicker.


You can also support your body’s natural defense mechanism by eating plenty of healthy foods, avoiding stress and exercising.


If you do not develop any symptoms, consider yourself lucky, but make sure you take measures not to pass HSV-1 on to others.


The time it takes for an outbreak to develop after kissing a person with a cold sore varies widely. It could take up to 20 days before you notice any signs that you contracted herpes.


I accidentally kissed my baby with cold sore. What should I do?

Neonatal herpes can be very dangerous because babies don’t have a well-developed immune system. The risk of passing HSV-1 to a baby is highest during the first month after birth.


Go and see a doctor if you kissed your baby during a flare-up.


If you notice any of the following signs in your baby, seek an immediate appointment with your healthcare provider:


  • Refusal to feed
  • Fever
  • Rash or blisters on the eyes, mouth or skin
  • Irritability


You should seek urgent medical attention for your infant if any of the following signs develop:


  • Difficulty waking up or unresponsiveness
  • Gasping for air, trouble breathing or rapid breathing
  • Lethargy or lack of energy
  • Blue skin or a blue tongue


Your doctor will usually treat your baby with an injection of an antiviral drug. Often the parent will also be prescribed medication.


In most cases, babies will recover well. However, make sure you seek treatment for your child immediately.  If left too long, the virus can spread and result in fatality.



When is it safe to kiss someone after a cold sore? In short, it’s never safe to kiss someone with a cold sore and it’s best to wait a few days after blisters have completely healed before kissing another person.


Remember, it can take 10 to 14 days for cold sores to heal. However, you can speed up the healing process with an antiviral medication.



  1. WHO. (2017, January 31). Herpes simplex virus. Retrieved from website:
  2. Harvard Health Publishing. (2015, April 28). Cold sores - Harvard Health. Retrieved November 6, 2019, from Harvard Health website:
  3. Opstelten, W., Neven, A. K., & Eekhof, J. (2008). Treatment and prevention of herpes labialis. Canadian family physician Medecin de famille canadien, 54(12), 1683–1687.
  4. James, S. H., Sheffield, J. S., & Kimberlin, D. W. (2014). Mother-to-Child Transmission of Herpes Simplex Virus. Journal of the Pediatric Infectious Diseases Society, 3 Suppl 1(Suppl 1), S19–S23.
  5. Allen, U. D., Robinson, J. L., & Canadian Paediatric Society, Infectious Diseases and Immunization Committee (2014). Prevention and management of neonatal herpes simplex virus infections. Paediatrics & child health, 19(4), 201–212.


Reviewed by Dr Roy Kedem, MD

Information last reviewed 07/12/21

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