Tuesday, July 5

Taking an antigen test before having dinner as a family on Christmas Eve: these are the deadlines and situations that you have to know in order for it to make sense

At the beginning of December, a Christmas meal among health workers in a Malaga hospital ended up causing an outbreak of more than 70 infected. According to these health workers, they went to the food after taking an antigen test and giving all negative results. However, a few days the confirmed positives began to occur.

This example can illustrate how taking an antigen test may not be a guarantee, especially if we do it at the wrong time, when it can be counterproductive, since it is possible that we do it in advance giving a negative result … but it becomes positive a few days later, when we attend a dinner with other non-cohabitants, even if we self-define the previous days.

Counting the days for the antigen test

The main risk is in the first days after infection. At that time we are already carriers of the virus, but no symptoms have appeared and the viral load is reduced, at a level that neither a PCR nor an antigen test can detect positivity. That is why it is possible that even if we do a pharmacy-bought antigen test and the result is negative, we are still in those first days after infection, and shortly after we begin to experience the first symptoms (dry cough, fever, muscle pain … .) or to be able to transmit the virus even if we are asymptomatic.

The ability to infect has its peak days in the first week after we begin to experience symptoms, after the days of incubation. Before, during the beginning of the incubation, it is neither transmittable nor detectable by any test. From the seventh day with symptoms, the risk of contagion decreases, and from the tenth day it is even lower (although still viable). In vaccinated people, especially those with a complete regimen, the possibility of experiencing symptoms, especially if they are severe, decreases. But they can still be infected, and infect others.

In the case of close contacts with positives or suspicions of having been infected (for having been in a risk context, such as with a crowd without a mask for hours in a closed space), an antigen test could not tell us with any reliability if we are infected or not until the third or fourth days after contact, and up to ten days later. In the case of not having had close contacts or being exposed to risk situations, if we experience symptoms compatible with COVID, we would not have to wait, since in that case an antigen test could detect the virus.

A possible situation for Christmas is to take an antigen test to be able to dine with the family on Christmas Eve without fear of being asymptomatic and being able to infect them. This makes sense if we do the test as soon as possible, almost before the family reunion, and if we are not going to live with them in the following days.. In that case, we may reach Christmas Eve in the incubation phase, without the ability to infect them, but a few days later we do have it, even though we are asymptomatic.

The results of these antigen tests, or of PCR tests in the case of attending a health center indicate:

  • Positive PCR: carrier of the virus, although not necessarily contagious.
  • Negative PCR: we are not in the contagion phase, but perhaps we are incubating it.
  • Positive antigens: carrier of the virus and contagious.
  • Negative antigens: not contagious, although possible carrier of the virus.

These are the autonomies in which it is mandatory to request the COVID passport to enter restaurants or discos

And here is our partner’s table Javier Jimenez with the details of each of the tests, including the antibody tests, which do not serve to detect if we are infected.

PCR

Antigens

Antibodies

Do they detect if we are infected?

Yes

Yes

No

Do you detect if we have overcome COVID-19?

No

No

No

Do they detect if we have antibodies?

No

No

Yes

What does a positive result mean?

Possible active infection

Possible active infection

Possible exposure to the virus

How are samples collected?

Nasopharyngeal, oropharyngeal, nasal, salivary, etc.

Nasopharyngeal, oropharyngeal, nasal, salivary, etc.

Blood, plasma or serum

Is there in self-diagnosis format?

No

Yes

Yes

How are they processed?

At the laboratory

At the sample collection site or at home (self-diagnosis)

In the laboratory, at the sample collection site or at home (self-diagnosis)



Reference-www.xataka.com

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