COVID's highly contagious? Much like influenza in a mild flu year
What should you do if one of your family members has COVID? Should you
1. Get them boosted, along with the rest of the family, ASAP?
2. Give them lots to drink, plus TLC?
3. Lock them in their bedroom until they produce a negative PCR test?
4. Ask the WHO for advice?
Beware: Dangerous disease!
Here’s what the WHO, the World Health Organization advises:
People with COVID-19 infection should (where possible) be isolated in a separate room, away from others in the home. If possible, close the door to stop air from moving from the infected person’s room into the rest of the home...
No other visitors should be allowed in the home when someone in the household has COVID-19 infection.
The WHO does add that children should not be shut up alone — one other person (and only one) should be designated to run the risk of interacting with them:
... children should not be isolated on their own. If possible, there should be only one person, who is healthy and not at high risk, in the household providing care to the child with infection. The designated caregiver should take care of the child at all times and monitor their symptoms and safety.
In Australia, the official advice is similar:
If someone you live with has COVID-19 they must isolate. Isolate means to stay at home away from other people for 7 days. They should stay in 1 room as much as they can. You should not go into that room. They should use a different bathroom if they can. If there is only 1 bathroom they should clean it every time they use it ... Only use the common areas of the house if they are not in there.
Various healthcare authorities in the United States suggest procedures more along the same lines, such as this guidance from Tallahassee:
It’s best for the person who has COVID-19 symptoms or who has tested positive to remain isolated from everyone else in the household. But we know for many people, that’s easier said than done.
If possible, do everything you can to avoid using the same rooms and restrooms as the person who has tested positive. That may mean isolating them to a single room or section of your home, leaving their meals at their door and communicating over the phone.
Quarantine or quarantine camp?
Some officials were clearly concerned that despite the plethora of such "good advice," people might still refuse to adopt it, and therefore they proposed more active means of quarantine. This is from Dr. Van Kerkove of the WHO's Health Emergencies Program, back in 2020:
In some senses, transmission has been taken off the streets and pushed back into family units. Now we need to go and look in families to find those people who may be sick and remove them and isolate them...
All these esteemed authorities see COVID-19 as a significant threat to humanity. The virus has been presented as not only virulent but also highly contagious, to the extent that even outdoor transmission was seen as a distinct possibility and people were kept an (arbitrary) six feet from one another in public places.
Here’s mainstream medicine website WebMD on how contagious COVID is:
Researchers say that on average, every person who has COVID-19 will pass it on to 2 or 2.5 others. One study says that number is even higher, with one sick person infecting between 4.7 and 6.6 others.
'Superspreading' was always a myth
According to two recent studies, however, all the abovementioned advice may be far too extreme, unless the person at risk of contagion is very vulnerable. At the recent annual IDWeek meeting of medical professionals, one of the presentations revealed new findings related to COVID transmission within households which would seem to invalidate the official guidance.
It’s important to note that IDWeek is no fringe medical conference. It is the joint annual meeting of the Infectious Diseases Society of America, the Society for Healthcare Epidemiology of America, the HIV Medicine Association, the Pediatric Infectious Diseases Society and the Society of Infectious Diseases Pharmacists. All of the presentations are firmly within the mainstream consensus and the findings on household transmission are tucked away in a wider study on vaccine efficacy. Nonetheless, MedpageToday saw fit to publicize them.
The article begins by stating that research conducted early in the COVID era showed that contagion within families was highly significant in spreading the virus:
Since early in the COVID-19 pandemic, epidemiologic studies demonstrated that household transmission was a key driver in the spread of SARS-CoV-2.
The study the article links to was published in December, 2020 and describes family homes as “high-risk settings” for the spread of COVID. This assertion was based on a meta-analysis of 54 studies of almost 80,000 people in total. The household secondary attack rate was determined to be 16.6 percent, compared to 4.8 percent among “close contacts.”
Secondary attack rate is a useful measure for estimating how contagious a pathogen is. A secondary attack rate of 16.6 percent means that 16.6 percent of the people exposed to the pathogen via an infected person will catch the illness themselves. If 10 people living in 20 households with a total of 110 people between them have COVID, and they infect 10 other people, the secondary attack rate is 10 divided by 100 (110 people minus the 10 who already have COVID) multiplied by 100%, which is 10%.
If a secondary attack rate (SAR) of 16.6 percent for household exposures sounds quite low, that’s because it is low in comparison to other pathogens. Seasonal influenza has a SAR anywhere between 5 and 15 percent depending on the year — and that’s population-wide SAR, not within a household.
Other diseases are far more contagious; smallpox, for example, is estimated to have a SAR of around 60 percent. Chickenpox is even more transmissible with a SAR of around 85 percent.
What this suggests is that even at the start of the “pandemic,” it was known that SARS-CoV-2 was not a superspreading phenomenon, despite all the scare headlines of “superspreader” events.
Indeed, the authors of this study seem to acknowledge this, writing:
Using an empirical analysis based on secondary attack rates and mean number of contacts per household, we found the proportion of households with any secondary transmission was lower than expected.
Less than 20% infection rate even within households
MedpageToday makes no mention of this observation, although it does mention later in the article that another meta-analysis (of 135 studies involving over 1.3 million people in total) conducted in 2022 found that the household secondary attack rate was 36.4 percent during the Alpha wave, 29.7 percent during the Delta wave, and 42.7 percent during the Omicron wave.
SARs of over 30 percent are certainly high. However, what these studies failed to account for was the possibility that what looked like in-house transmission was in fact contagion from an outside source, which would affect the SAR calculation. Accordingly, several researchers set out to investigate this using genomic analysis to determine the specific variant of SARS-CoV-2 in both the original source of the virus and the person presumed to have contracted it from them.
Two studies presented at this year's IDWeek annual meeting focused on leveraging genomic analysis to gain a better understanding of whether COVID infections in households represent transmission between household members or the introduction of new infections.
The first study was conducted by Kathryn Stephenson, MD, MPH, of Harvard Medical School in Boston. 38 households were enrolled in the study; each household had one COVID case.
Following up two weeks later, Stephenson found that in 58 percent of the households someone additional tested positive for COVID. Out of a potential 66 people who were exposed to someone with the virus, 39 percent tested positive. This would seem to confirm the idea that SARS-CoV-2 is highly contagious and that severe measures to contain it are warranted.
However, Stephenson then tested all the original sick people and those sickened and found that the variants didn’t always match, indicating that the source of the secondary infection was not the sick family member. Removing these cases from the picture, the eventual SAR turned out to be just 18.4 percent.
Two shots or no shots — the same rate of spread
This 18.4 percent SAR figure is related to the Omicron period, and is much lower than the 42.7 percent of the meta-analysis. Looking more closely at the data reveals more interesting findings. Stephenson’s research subjects were virtually all “vaccinated” and most had received three shots (two plus a booster). The meta-analysis categorizes the results according to shot status: no shot, partially vaccinated, fully vaccinated, booster.
The SAR for the Omicron period in the meta-analysis was 51 percent for the two-shot (“fully vaccinated”) cohort. That dropped to 38 percent for those who got a booster shot, which is still a lot higher than the 18.4 percent Stephenson found.
Unfortunately, Stephenson did not investigate the non-injected population. In the meta-analysis, the SAR for the Omicron period for those who never got a shot was 51 percent — that is, identical to the SAR for those who got two shots.
The SAR for the “partially vaccinated” in the meta-analysis was 77 percent.
Stephenson came to this conclusion:
Our study found that the risk of SARS-CoV-2 in exposed households is very high, consistent with previous reports.
Very high in comparison to what? The SAR is actually very low in comparison to most if not all previous studies as well as in comparison to many other diseases.
She added that steps should be taken to reduce transmission, given that the shots are clearly not very effective:
Further interventions to block household transmission should be studied, especially in the now-common scenario when population immunity and vaccine coverage are high but viral variants are increasingly immune evasive.
All those days you spent in quarantine after being in contact with COVID? Wasted
The second study cited by MedpageToday came to similar conclusions using similar methods. A larger study, it followed 1,103 households, 67 percent of which had at least one family member with COVID. 24 percent of the households had at least one apparent case of contagion, but 7 percent of these involved “more than one viral lineage,” suggesting that the real source of the infection was from outside the household.
MedpageToday summarized the findings as follows:
What can we take away from these two studies? Household contacts of a person newly diagnosed with COVID-19 are certainly at high risk for SARS-CoV-2 infection in the following weeks. However, this may not only be due to heightened risk of transmission between household members, but also -- perhaps not so surprisingly -- to an overall increase in SARS-CoV-2 transmission in the community where different strains may be circulating.
A more honest analysis of the findings might be:
> SARS-CoV-2 is not nearly as contagious as was once thought — something in the region of a bad influenza year among family members, and in the region of a mild influenza year among the general population.
> People are more likely to catch COVID from other people they live with, unsurprisingly. However, it’s still far from a foregone conclusion that you’ll catch it from an infected family member. Most of the family will actually remain uninfected.
> All this applies to people who got the shots. That is to say, you’re as likely to catch COVID from someone in your household, even if you’ve been boosted, as you are to get flu from the checkout clerk at the supermarket with no flu shot to “protect” you.
The information contained in this article is for educational and information purposes only and is not intended as health, medical, financial or legal advice. Always consult a physician, lawyer or other qualified professional regarding any questions you may have about a medical condition, health objectives or legal or financial issues.
