Past infections can be identified when undergoing an antibody blood test detects the Nucleocapsid (n) proteins.

The ubiquitous presence of the highly contagious coronavirus around us, life returning to normal with the lifting of restrictions and the precedence of asymptomatic cases often make you wonder what if they get a Covid-19 infection without knowing it. Even several studies have shown that the diagnosed cases of Covid-19 are just the tip of the iceberg of many undiagnosed cases. Here’s everything you need to know about having Covid without knowing it and whether you should be concerned.

How Covid is diagnosed and how to know if there was an infection before without symptoms

Most people undergoing Covid testing such as RT-PCR are symptomatic or have someone close to them with symptoms ranging from fever to upper respiratory tract congestion. A smear is taken for the results. In 2022, with a massive spread of infections, mild in most cases, many did not take a PCR or RAT test but assumed they were positive and were quarantined.

But past infections can be identified if undergoing a blood test detects the Nucleocapsid (n) proteins. They are the antibodies launched by the body’s natural immune response to prevent the virus from attaching to human cells. They are formed in 1-3 weeks and last for six months. However, detection of antibodies to the S protein only indicates vaccination (but not infection).

Limitations in Covid Antibody Testing

There is still much to learn about the body’s immune response to Covid-19. Not everyone can develop a detectable amount of antibodies, and in some people their levels decrease over months. Moreover. Other circulating viruses, such as the common cold, can also prompt the body to make N proteins, leading to ‘false positives’

But antibody testing needs to be done in special cases like knowing the effectiveness of the vaccine, for serosurvey, diagnosing complications after infection or of the person eligible for a particular treatment etc. It can also be used for assessing of the infection rate of the background population.

Antibody Testing on a Population

Antibody testing is primarily done for seroprevalence studies to find out whether a particular population has achieved collective or herd immunity. Blood from blood banks representing the general population is used. A peer-reviewed study by the World Health Organization that has yet to be reviewed reported the results of a meta-analysis of more than 800 seroprevalence studies conducted around the world since 2020.

According to the report, by July 2021, 45.2% of the world’s population had SARS-CoV-2 antibodies, eight times the estimate from a year earlier. Fresh serosurvey will understand to what extent the Omicron wave produces antibodies in the general population.

How having a covid infection unknowingly could matter in the future

Some research says that people with mild or asymptomatic infection have a less effective antibody response compared to people with severe disease, but that cannot be linked to the response to reinfection. Also, knowledge about having antibodies from previous infections should not deter one from taking Covid vaccination, which still remains the best protective care.

Those who have a more severe first bout of Covid disease with a higher viral load are more likely to develop persistent or recurring symptoms such as shortness of breath, muscle fatigue, exercise intolerance.

take away

As we enter the third year of the Covid-19 pandemic and as one in three infections may be asymptomatic, it is likely that many of us who have not been diagnosed with a PCR are infected without knowing it.

But unless you are experiencing conditions such as persistent fatigue, brain fog, you may be least affected and know that your COVID infection status is unlikely to provide much practical benefit. In such cases, antibody testing should only be performed for specific medical or public health indications.

This post Covid-19: Is it possible to have the infection without knowing it and should you be concerned?

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