Why are you still Covid-free? – Lifestyle News

This story is reprinted with permission from The Conversation.

Throughout the pandemic, New Zealand has recorded 1.89 million Covid-19 cases, the majority of which have occurred this year.

This is definitely an underestimation as not everyone tests for Covid-19 or reports a positive result.

Then there are people who have had multiple confirmed exposures to Covid-19 during the pandemic but still have no symptoms and test positive.

They are known as Novid. So what do we know about them?

First, we may not actually be novids

Some people who claim to have never been infected with Covid-19 may be surprised to learn that they have antibodies in their blood that target viruses that may have been produced only by the infection.

The reliance on home rapid antigen tests (RATs), which are less sensitive than PCR tests, makes it difficult for many people to tell for sure if they have Covid-19.

Under ideal test conditions, the best tests detect SARS-CoV-2 infection with a probability of over 95%. However, the actual detection rate is even lower.

If mild symptoms do not last long, they are less likely to test repeatedly and may miss the window to get a positive result.

At this point, it is important to distinguish between being infected with SARS-CoV-2 and experiencing the illness (Covid-19) caused by this infection. You can get infected without experiencing Covid-19 symptoms. This is called an asymptomatic infection.

The proportion of asymptomatic cases of the Omicron subvariant is unknown. Early in the pandemic, she was asymptomatic in 1 of her 6 of those infected, but at Omicron she could reach more than 50%.

Therefore, many Novids were infected with SARS-CoV-2 and developed antibodies to the virus, but did not experience or notice Covid-19 symptoms at the time, were not tested, and were not infected. remained unaware of (and they were unwittingly transmitting the virus).

What role does the immune system play?

Everyone’s immune system is different. How the immune system responds to a particular infection depends on genes, gender, age, diet, sleep patterns, stress level, history of other infections and illnesses, medications, vaccination status, level of viral exposure, etc. , is influenced by many factors.

So are some people less likely to get Covid-19 because they have stronger immune systems?

The state of our immune system always affects our susceptibility to disease. It is therefore surprising that the people most vulnerable to severe Covid-19 are those with weakened immune systems, either because they have chronic illnesses, because they have weakened immune systems, or because they are older. That’s not the point.

Another important variable is viruses. SARS-CoV-2 continues to evolve and new Omicron variants continue to emerge. This affects how the virus interacts with us and the relative impact of various factors that affect immune protection and susceptibility.

SARS-CoV-2 has proven particularly adept at evolving to generate viral variants that can circumvent established immune protection. Additionally, our immune defenses are not stable and begin to wane after a few months if not bolstered by vaccination or infection.

Are my genes protecting me?

Consider something relatively stable: your genes.

Scientists looking for associations between specific genes and diseases can perform genome-wide association studies. Because the impact of individual genetic variants on disease risk is usually so small, identifying them requires large numbers of people and takes into account other variables that make us all different. I have.

In one such study, researchers compared the genomes of about 50,000 people infected with Covid-19 with those of 2 million people with no known infection.

They identified regions (loci) in the genome associated with Covid-19 infection and other genetic regions associated with disease severity. So this is evidence that certain genes alter her Covid-19 risk, as it does for many other diseases.

Association is not causation, but these types of genomic studies will help us better understand the biology of Covid-19 and ask questions such as who may be at risk for severe illness and long-term Covid. It points the way to support the development of new treatments to address and prevent these. result.

Another study identified a small number of severe Covid-19 patients with rare genetic mutations. These may be directly related to deficiencies in antiviral immunity.

So for a very small number of people, their genes seem to make them more susceptible to Covid.

Can I get immunity from a previous infection with a similar virus?

SARS-CoV-2 is not the only respiratory coronavirus that regularly infects humans. His four other 229E, HKU-1, OC43, and NL63 have similarities to SARS-CoV-2.

Most adults have multiple infections with these viruses throughout their lives. This suggests that immunity generated by lifetime and/or recent exposure to these other coronaviruses may generate immunity that provides some degree of protection against SARS-CoV-2 infection and symptomatic Covid-19. increase the

Further research is needed to better understand this, but the existing evidence is compelling and certainly plausible.

In short, there are many reasons why people who interact, and inevitably interact, with Covid-19 infected people believe they themselves have not had Covid. For most Novids, a combination of vaccination, a healthy immune system, smart decisions and good luck has kept them Covid-free so far.

Of course your luck runs out, so enjoy your Novid status.