the Contagiousness of Chickenpox and Blister Infections

Q: the Contagiousness of Chickenpox and Blister Infections

Dear Mr. <br>Gina：<br>1. <br>Chickenpox (Varicella) refers to the disease caused by the initial infection with the varicella-zoster virus (VZV), which is most commonly seen in children under the age of 10, although it can occasionally occur in young adults. <br>The early symptoms

The contagiousness of blisters?

Hello, doctor.
Recently, our school has switched to remote learning due to confirmed cases.
Just the day before yesterday, a friend in the dormitory showed me that there was a chickenpox infection on their floor, so they started disinfecting again.
This morning, when I went for a follow-up appointment at the dermatology clinic for my acne, I overheard a pharmacist talking to a gentleman about how to apply medication to his blisters, mentioning that they probably wouldn't burst.
This suddenly reminded me of what my classmate said about chickenpox, and I realized that I had just sat on the same couch that the gentleman had used.
Is it possible that I could get infected? I’m not sure if the blisters are the same as those associated with chickenpox.
Also, due to medical ethics and patient privacy, I felt uncomfortable asking the doctor whether the two gentlemen's conditions were contagious.
However, I am still worried that I might get infected just by sitting in the same spot, especially since my friend mentioned that the school said this virus is highly contagious, and everyone on their floor has been asked to undergo thorough disinfection.

Gina, 20~29 year old female. Ask Date: 2020/04/23

Dr. Xiao Yongxun reply Family Medicine

Dear Mr.
Gina:
1.
Chickenpox (Varicella) refers to the disease caused by the initial infection with the varicella-zoster virus (VZV), which is most commonly seen in children under the age of 10, although it can occasionally occur in young adults.
The early symptoms resemble those of influenza, with mild fever and loss of appetite lasting about 1 to 2 days, followed by the appearance of a rash that develops into vesicles, pustules, and crusts.
The rash typically starts on the face and trunk and spreads outward to the rest of the body.
Scratching the lesions can lead to scarring.
Other complications may include encephalitis and pneumonia.
After recovery, the virus remains dormant in the dorsal root ganglia and may reactivate in adulthood, causing herpes zoster (shingles).
2.
The incubation period for chickenpox is 2 to 3 weeks, generally ranging from 13 to 17 days.
In terms of contagiousness, the individual is contagious from 5 days before the rash appears (usually 1 to 2 days prior) until all lesions have crusted over, with the highest contagiousness occurring just before the rash develops.
The contagiousness of a shingles patient can last up to 1 week after the appearance of vesicles.
3.
The mode of transmission is primarily through direct skin contact, respiratory droplets, or airborne spread.
Contact with the vesicles of a shingles patient can also lead to transmission.
Additionally, indirect transmission can occur through objects contaminated with fluid from the vesicles or mucosal secretions.
Crusts are not contagious.
4.
I am not aware of whether you have had chickenpox or received the chickenpox vaccine in the past.
If you have had chickenpox or been vaccinated, your chances of contracting chickenpox again are very low.
However, if you have never had chickenpox or received the vaccine, you are indeed at risk of contracting the disease.
5.
There are many diseases that can cause vesicles, with differential diagnoses numbering in the dozens; some are contagious while others are not.
Therefore, you should consult your dermatologist to clearly communicate your concerns and make an informed decision.
6.
Given the recent outbreak of COVID-19, where everyone is wearing masks and practicing hand hygiene, I believe the likelihood of you contracting chickenpox is quite low.
If you have further questions, please discuss them with your family physician to alleviate any undue worry.

Reply Date: 2020/04/23

More Info

Chickenpox, caused by the varicella-zoster virus, is indeed highly contagious. It spreads primarily through respiratory droplets when an infected person coughs or sneezes, and it can also be transmitted through direct contact with the fluid from the blisters of someone who has chickenpox or shingles. The virus can remain in the air for a short time after an infected person has left the area, which is why environments like schools can see rapid spread when one case is identified.

In your situation, sitting on a sofa previously occupied by someone with blisters does raise some concern, but the risk of transmission in this manner is relatively low. Chickenpox is most contagious from about two days before the rash appears until all the blisters have crusted over. If the individual you encountered was not showing any signs of chickenpox, the likelihood of transmission through indirect contact (like sitting on the same sofa) is minimal. The virus does not survive long outside the human body, and the risk of contracting chickenpox from surfaces is significantly lower compared to direct contact with an infected person.

It’s important to note that if you have had chickenpox in the past or have been vaccinated against it, you are likely immune and would not contract the disease again. Vaccination is a highly effective way to prevent chickenpox and its complications, and it is recommended for children and adults who have not had the disease.

To protect yourself in a school environment where there is a known outbreak, consider the following precautions:
1. Vaccination: Ensure that you and your family members are up to date with the chickenpox vaccine. This is the most effective way to prevent infection.

2. Avoid Close Contact: If you know there is an outbreak, try to limit close contact with individuals who may be infected. This includes avoiding sharing personal items like towels or utensils.

3. Good Hygiene Practices: Wash your hands frequently with soap and water, especially after being in public spaces or after touching surfaces that may have been contaminated.

4. Monitor Symptoms: Be vigilant for any signs of chickenpox, such as fever, fatigue, and the characteristic itchy rash. If you develop symptoms, contact a healthcare provider promptly.

5. Stay Informed: Keep up with any announcements from your school regarding health and safety measures, and follow any guidelines provided by health authorities.

In conclusion, while the concern about potential exposure is valid, the risk of contracting chickenpox from sitting on a sofa previously occupied by someone with blisters is quite low, especially if they were not symptomatic at the time. Maintaining good hygiene and ensuring vaccinations are up to date are your best defenses against chickenpox and other contagious diseases. If you have any further concerns or develop symptoms, it is advisable to consult with a healthcare professional for personalized advice and guidance.

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