Viral shedding what does it look like

Certain groups have been associated with prolonged SARS-CoV-2 shedding, including males, children , older adults, and people with compromised immune systems. But, by sticking to COVID-safe guidelines such as keeping an adequate distance from others, wearing a face mask, and practising hand hygiene, we can minimise the risks from a person unknowingly shedding infectious virus.

Reports of reinfection — in the sense of a new infection, rather than prolonged or intermittent shedding of the same one — have been limited to date. One source collating confirmed reinfection cases indicates there have been just 26 worldwide. Evidence we have from other coronaviruses suggests the risk of reinfection may be lower in the first 90 days after initial infection. Some studies on COVID, both published and not yet formally published in a peer-reviewed journal , suggest immunity may last for several months.

But we need more evidence on this topic, which we will accumulate as time passes. While the virus appears to be under good control in Australia, prolonged viral shedding and reinfection are probably two of the most important drivers of SARS-CoV-2 community transmission around the world. This is why early messaging during the pandemic was that wearing a mask was a way to protect those around you.

This became particularly important as we learned that people infected with SARS-CoV-2 can spread the virus a few days before they develop symptoms.

Viral shedding can occur following vaccination if the vaccine contains live, weakened viruses because that type of vaccine causes immunity through viral reproduction.

Examples of routinely used live, weakened vaccines include measles, mumps, and rubella MMR ; chickenpox; rotavirus; and the intranasal influenza vaccines. The oral polio vaccine OPV also contains live, weakened virus.

While OPV is no longer used in the U. The yellow fever vaccine, while not routinely used in the U. An important distinction between a viral infection and vaccination with a live, weakened viral vaccine is the amount of virus that is shed. If vaccination causes shedding, it typically results in significantly lower quantities of virus being shed, and the shed virus particles are less likely to cause disease because they are the weakened form used to make the vaccine.

However, a few exceptions exist. For example, if someone is immune compromised, they might shed virus for a longer period of time because their immune system has trouble stopping viral replication. For this reason, some people with immune-compromising conditions cannot receive live, weakened vaccines.

Another consideration is that people not immune to the disease could get infected through viral shedding. Sometimes this is beneficial as in the case of the oral polio vaccine, which causes more than just vaccinated people to be protected against polio. This type of protection is called contact immunity.

But on occasion, viral shedding can also result in an infection with symptoms, such as when an unimmunized person comes into contact with the chickenpox rash of a vaccinated person and develops a mild case of chickenpox. The source of this confusion is twofold. First, people may not distinguish between the reproduction of a virus and the COVID vaccines causing our bodies to produce the spike protein.

Second, like the whisper-down-the-lane game, talking down the line further confounds the confusion. In sum, viral shedding is an issue when someone is infected with the virus that causes COVID, but not when they are vaccinated against it. Download a PDF version of this article. Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.

Instead, they use other technologies to train our bodies to recognise SARS-CoV-2 and to mount a protective immune response should we ever be exposed to it. For instance, the AstraZeneca vaccine is a viral vector vaccine. This uses a modified chimpanzee virus to carry into the body the genetic instructions to produce the SARS-CoV-2 spike protein. Your body then uses these instructions to make the spike protein, and to raise a protective immune response.

The Pfizer vaccine is an mRNA vaccine, which contains the genetic material to code for the spike protein. Once inside your cells, your body uses those instructions to make spike protein, again raising a protective immune response.