The Times Australia
The Times World News

.
The Times Real Estate

.

Someone in my house has COVID. How likely am I to catch it?

  • Written by Hassan Vally, Associate Professor, Epidemiology, Deakin University
Someone in my house has COVID. How likely am I to catch it?

Throughout the pandemic, one of the biggest COVID risks has been sharing a house with someone who is infectious.

Given how contagious COVID is, especially more recent variants, you’d imagine if you lived with someone who has COVID it would be inevitable you’d get infected.

But this isn’t the case. A recent study suggests you have[1] a 42.7% chance of catching COVID from a housemate who tests positive to Omicron.

That means if someone introduced the Omicron variant to a household of six, you would expect two of the remaining five household members, on average, to become infected.

How is household transmission measured?

We use the “secondary attack rate” to describe the average number of secondary infections among a group of exposed people, once a virus has been introduced into to a particular setting such as a household. It accounts for a number of different factors including:

  • how infectious the virus is
  • how high the viral load of the infectious person is, and how efficiently they shed the virus
  • the susceptibility of others present
  • the characteristics of the setting such as crowding and ventilation.

The secondary attack rate[2] is an average, and transmission varies considerably between households. So some households see all members infected, while others have little or no transmission.

From early in the pandemic we’ve also seen “superspreading”, where a small number of people are responsible for a large proportion of new COVID cases.

Conversely, a large proportion of people infected don’t spread it at all[3].

Read more: How to prevent COVID-19 ‘superspreader’ events indoors this winter[4]

How has household transmission changed through the pandemic?

A meta-analysis[5] (where the results of earlier studies are pooled together) published in April combined the results from 135 studies and 1.3 million people across 136 countries published in the Journal of the American Medical Association (JAMA).

It estimates the household secondary attack rate for the original virus was 18.9%. So your risk of being infected with COVID if you shared a house with one or more infected people was approximately one in five.

Person lays on couch in a hoodie, under a blanket.
Some people don’t spread COVID at all. Rex Pickar/AAP[6]

The increase in infectiousness of new variants that emerged from late 2020 translated to an increase in household transmission. The Alpha variant had a a household secondary attack rate of 36.4%. This decreased to 29.7% for the Delta variant, before increasing again to 42.7% for Omicron.

However, even studies as large and comprehensive as this are limited in their ability to make direct comparisons of all the factors that may impact secondary attack rates, such as the household environment, the behaviour of household contacts and the use of masks to name a few. And this study did not include the newer Omicron variants.

Why has has the household secondary attack rate varied?

The secondary attack rate for the Delta variant declined compared to the Alpha variant[7], despite its increased infectiousness. This is likely explained by rising immunity in the population – both due to vaccination and prior infection.

While vaccines were not as effective against Delta as previous variants, and the protection waned over time, they still reduced the risk of household transmission.

Read more: No, vaccinated people are not 'just as infectious' as unvaccinated people if they get COVID[8]

Despite a significant increase in the infectiousness of the Omicron variants and their immune-escape properties[9], the risk of being infected in a household was still only estimated to be 42.7%. Increased immunity in the population is likely the reason it isn’t higher.

Vaccination reduces transmission

The reduction in the household secondary attack rate was greater[10] when households had received their booster vaccination.

The takeaway is that sharing a household with an infectious person doesn’t mean you will inevitably become infected, but being fully vaccinated helps reduce the spread of Omicron among household contacts.

Read more: New COVID variants may be more transmissible but that doesn't mean the R0 – or basic reproduction number – has increased[11]

Read more https://theconversation.com/someone-in-my-house-has-covid-how-likely-am-i-to-catch-it-189386

The Times Features

Best Deals on Home Furniture Online

Key Highlights Discover the best deals on high-quality outdoor furniture online. Transform your outdoor space into a stylish and comfortable oasis. Explore a wide range of d...

Discover the Best Women's Jumpers for Every Season

Key Highlights Explore lightweight jumpers for spring and summer, ensuring breathability and ease. Wrap up warm with cozy wool jumpers for the chilly autumn and winter season...

Uncover the Elegance of Gorgeous Diamond Tennis Necklaces

Key Highlights Diamond tennis necklaces are a timeless piece of jewelry that exudes elegance and sophistication. They feature a continuous line of brilliant-cut diamonds, cre...

Dental Implants vs. Dentures: Which Is Better for You?

When it comes to replacing missing teeth, two of the most common options are dental implants and dentures. Both have their advantages and disadvantages, so choosing between them ...

What Neck Pain Really Means (And Why It’s More Than Just Poor Posture)

Neck pain is often brushed off as something temporary — a tight spot after a long day at the desk or a poor night’s sleep. But when the discomfort keeps returning, it could be a ...

The Work of Gosha Rubchinskiy: Fashion, Culture, and Youth

From Designer to Cultural Architect Gosha Rubchinskiy is not just a fashion designer—he's a cultural force. Born in Moscow in 1984, Rubchinskiy began his career in fashion in t...

Times Magazine

The Essential Guide to Transforming Office Spaces for Maximum Efficiency

Why Office Fitouts MatterA well-designed office can make all the difference in productivity, employee satisfaction, and client impressions. Businesses of all sizes are investing in updated office spaces to create environments that foster collaborat...

The A/B Testing Revolution: How AI Optimized Landing Pages Without Human Input

A/B testing was always integral to the web-based marketing world. Was there a button that converted better? Marketing could pit one against the other and see which option worked better. This was always through human observation, and over time, as d...

Using Countdown Timers in Email: Do They Really Increase Conversions?

In a world that's always on, where marketers are attempting to entice a subscriber and get them to convert on the same screen with one email, the power of urgency is sometimes the essential element needed. One of the most popular ways to create urg...

Types of Software Consultants

In today's technology-driven world, businesses often seek the expertise of software consultants to navigate complex software needs. There are several types of software consultants, including solution architects, project managers, and user experienc...

CWU Assistive Tech Hub is Changing Lives: Win a Free Rollator Walker This Easter!

🌟 Mobility. Independence. Community. All in One. This Easter, the CWU Assistive Tech Hub is pleased to support the Banyule community by giving away a rollator walker. The giveaway will take place during the Macleod Village Easter Egg Hunt & Ma...

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

LayBy Shopping