Why Do Some People Get Covid When Others Don’t? Here’s What We Know So Far. Complete Info!

The reasons why some people never obtain Covid — the “never Covid” cohort — are increasingly being studied.
Covid instances have been seen in close-knit groups of couples, families, and coworkers, but not everyone has been infected.
This could be related to earlier infection with a similar virus or heredity.

One of the great mysteries of the Covid-19 pandemic is why some people get Covid and others don’t, even though they’re equally exposed to the virus.

But there are also countless instances of couples, families, and coworkers who caught the illness but not everyone.

According to research, the risk of infection inside a family after one case is positive is “not as high as you’d think,” said Danny Altmann, professor of immunology at Imperial College London.

The reasons why some people never obtain Covid — the “never Covid” cohort — are increasingly being studied.

Imperial College London published additional study last month revealing that patients with higher numbers of T cells from common cold coronaviruses were less likely to contract SARS-CoV-2, the virus that causes Covid-19.

 People Get Covid

Why Do Some People Get Covid When Others Don’t Here’s What We Know So Far

“We’ve been anxious to understand why being exposed to the SARS-CoV-2 virus doesn’t always result in infection,” said first author Dr Rhia Kundu of Imperial’s National Heart & Lung Institute. Infection with other human coronaviruses, such as the common cold, can protect against Covid-19 infection, she said.

But she warned, “While this is a significant discovery, it is only one method of protection, and no one should rely only on it. Instead, get fully immunized, including a booster dose, to avoid contracting Covid-19.”

People who have definitely been exposed to sick close contacts in their household, yet are resistant to infection, are being studied closely, said Warwick University’s Lawrence Young, a molecular oncology professor.

Early evidence suggests these people have inherent protection from earlier infections with common cold coronaviruses. “Why some individuals maintain levels of cross-reactive immunity is unknown,” he said.

Your Covid vaccination status may also play a role in whether you are more susceptible to Covid than others. Coronaviruses are a vast family of viruses that cause illness ranging from the common cold to more severe diseases or infections.

Covid immunization is now widely available in most Western countries, albeit the coronavirus vaccine used and when varies by population.

Many countries are also vaccinating younger children and giving booster doses to prevent as many people as possible from the more transmissible but less clinically severe omicron variety.

Less severe infections, hospitalizations, and deaths have been shown to be associated with Covid vaccinations. These anti-infection agents are not 100% efficient, and the protection they confer wears off with time, and is now undermined by the omicron version.

According , the reason why some people get Covid while others don’t is “well recognized and presumably relates to protection from vaccination, prior infection, or both.”

“We know that many patients have gotten omicron illness despite being fully vaccinated, including a booster shot. Vaccination reduces the risk of contracting omicron, although reactions vary. After extensive exposure, some people catch it and others don’t “stated he

Mantra Nguyen, RN, replaces an oxygen mask for a patient in the Covid-19 ICU at United Memorial Medical Center in Houston.

Mantra Nguyen, RN, replaces an oxygen mask for a patient in the Covid-19 ICU at United Memorial Medical Center in Houston.

“Certainly cross-reactive immunity from past infections with common cold coronavirus is likely to be a key impact,” said Young of Warwick University, “especially as these patients may have additional immunological benefits from already having been vaccinated.

Continued research into “never Covid” individuals will help researchers better understand the immune response to SARS-CoV-2, Young asserted, and “how this information may be utilized to build universal variant-proof vaccines.”

In the pandemic, patients with Covid have shown varying responses to the virus, with one having severe symptoms and the other being asymptomatic.

Our DNA may hold the key. “It’s a crucial question,”

“Variations across people’s immune systems make a difference, at least to whether or not you have symptomatic disease,” he said.

Some HLA types are more or less likely to develop a symptomatic, or asymptomatic, infection, he added.

“The HLA genes influence your immunological response. They influence your response to SARS-CoV-2. For example, those with HLA-DRB1*1302 are more prone to get sick “Altmann said.

Is it the tests?

The professor also cited the initial results of a British human challenge trial, in which 36 healthy young adults were purposely exposed to Covid, yet only half were infected.

Why does pipetting an identical virus dose into people’s noses infect 50% while not infecting the other 50%? wondered Altmann, referring to the trial’s method of infecting participants.

Essentially all trial participants were given a tiny dosage of the virus via drops up the nose, and then closely watched by clinical staff for two weeks.

16 of the 18 infected participants developed mild-to-moderate cold-like symptoms, including a stuffy or runny nose, sneezing, and a sore throat.

The study’s authors claim it’s the first to provide extensive data on early infection, before and throughout symptoms. The average time from initial exposure to virus detection and early symptoms (incubation period) was 42 hours among the 18 infected participants, much less than previous estimates of 5-6 days.

The amount of virus (viral load) identified in participants’ nose or throat swabs increased dramatically after this period. However, large levels of live (infectious) virus were still detected in lab testing up to nine days after inoculation, and up to 12 days for others.

On December 28, 2021, in Buenos Aires, Argentina, a couple wears protective masks as the Omicron version spreads.

Also fascinating was the viral distribution. While the virus was found in the throat early (40 hours versus 58 hours in the nose), viral levels were lower and peaked sooner in the throat. The virus peak levels were higher in the nose than in the throat, indicating a larger risk of virus transmission from the nose than the mouth.

This study found that while there is a risk of “missing infectious virus early in the course of infection, especially if only nasal testing is done,” the data overall support the use of lateral flow tests to detect infectious persons.

“We discovered that lateral flow tests generally correspond strongly with viral infection,” said study main investigator Professor Christopher Chiu. In the first few days, they may be less sensitive, but if used correctly and consistently, they can significantly slow viral spread.

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