Risk of infection through shingles
In contrast to chickenpox, shingles is much less contagious. Both diseases are caused by the same virus, the varicella zoster virus. The only possibility of transmission of shingles is in direct contact with the highly infectious content of the blisters (smear infection).
Transmission via air or respiration (droplet infection) is not possible. In addition, the contents of the vesicles containing the virus can only make people ill who have never had contact with the virus. This means that only people who have never had chickenpox can get sick from the shingles virus.
For these people, contact with the contents of the vesicles always leads to an initial infection with chickenpox, even if the pathogens originate from the vesicles of shingles. (“No shingles without chickenpox”). For people who have already been infected with chickenpox, the varicella zoster viruses do not pose a renewed danger. There is no direct infection with shingles.
Pregnant women and other persons at risk
In principle, pregnant women and the unborn child are also not at risk from the varicella zoster virus if they have already had the disease or have been vaccinated before pregnancy. If the pregnant woman has not had chickenpox in her previous life and has not been vaccinated against chickenpox (varicella), this can lead to the abortion of the unborn child. The reason for this is that if the expectant mother is infected with varicella during pregnancy, the viruses can be transmitted to the child via the placenta.
Similarly, a chickenpox infection of the mother shortly before or shortly after birth is a major health risk for the newborn. For this reason, people with chickenpox or shingles should avoid contact with pregnant women to avoid any risk. In addition to pregnant women, immunocompromised patients (e.g. cancer patients or HIV patients) must be protected from infection.
Duration of the risk of infection
How long are you contagious for others if you have shingles? In the case of shingles, non-immunized people, i.e. those who have not been vaccinated and who have not yet contracted chickenpox, can become infected with the virus through contact with the contents of the vesicles. Since the infection always occurs through contact with the virus-containing secretion of the skin blisters (“smear infection”), there is a danger of infection until the blisters are completely dried out and encrusted. This lasts up to two to three weeks.
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