Showing posts with label COVID-19. Show all posts
Showing posts with label COVID-19. Show all posts

08 May 2022

COVID-19 Mystery: Based on a True Story


The mystery: ten friends gathered for a weekend pre-wedding party. After spending the weekend together, only five of them got COVID-19.

Why did only half of the people get infected?

?

It is highly likely they were infected with the omicron variant – the dominant variant at this time – which is very contagious.

“The Omicron coronavirus variant was likely the fastest-spreading virus in human history. One person with the measles virus – a standout among infectious microbes – might infect 15 others within twelve days. But when Omicron suddenly arrived this past winter, it jumped from person to person so quickly that a single case could give rise to six cases after four days, 36 cases after eight days, and 216 cases after twelve days.”

So asked another way, how did five party goers avoid getting omicron?

Let’s set the stage with what we know of protections against omicron

First, all those at the party had three doses of the COVID-19 vaccine – so there was no difference in vaccinations between those who got infected wth COVID-19 and those who didn’t. However, they were all about 5 months past their third dose of vaccine and vaccines wane, making them vulnerable to be infected at this point in time. 

None were eligible for their fourth doses because they were all in their twenties – too young for fourth dose eligibility.  

However, they took a very important precaution: understanding they were vulnerable to infection they all did rapid antigen tests on Friday morning before meeting on Friday afternoon. All of them tested negative.

Did the rapid antigen tests miss an infection? How reliable are rapid antigen tests? Research suggests they aren't entirely accurate, “Medical experts continue to warn that a negative result on a rapid test doesn't necessarily mean you don't have COVID-19." New Swiss research, which is yet to be peer-reviewed, suggests some rapid tests have "significantly lower sensitivity" to Omicron than to the Delta variant.

So, could this have been a problem with one or more people being infected with COVID-19 but not testing positive on the rapid antigen test? Unlikely, because they all spent a weekend together, not wearing masks and doing what young people do – hugging, laughing, occasionally bursting into song and sharing bedrooms. Is it possible that half the people avoided infection given all this?

COVID19 is airborne, so a person gets infected “when infectious particles that pass through the air are inhaled at short range”, a process otherwise known as “short-range aerosol or short-range airborne transmission”… transmission can [also] occur through “long-range airborne transmission” in poorly ventilated or crowded indoor settings “because aerosols can remain suspended in the air or travel farther than conversational distance.”

If 10 young people share space with one or more infected persons, sharing the same air for an entire weekend, wouldn’t it be likely that more than half get infected? 

To answer this mystery, it’s helpful to fast forward to the end of the weekend. As all ten people were leaving, there were unmasked hugs, chats and laugher. Then 5 of the people piled into one car and 5 into the other. This is where the mystery becomes less baffling: all the people in one car got infected and none in the other car got infected.

Again – the question is why? What was in one car but not the other? What was in one car but not present all weekend long that infected everyone in the car only?

There are two important concepts to break down: the duration of safety with rapid antigen tests and the incubation period of omicron.

Rapid antigen tests, even if they accurately detect infections, are only useful for that moment in time. So, one can be accurately negative today and accurately positive tomorrow.

How?

Here we need to look at the incubation period of omicron. An incubation period – for this mystery – is best seen as the time from the moment a person is infected to the time they are infectious. That time varies from three to five days.

So lets’s backtrack to the week before the get together. Someone got infected with omicron that previous week. They were asymptomatic when the weekend began and – very importantly – it was too early in the infection for the rapid antigen test to detect this early infection. As the weekend wore on, this person still remained infected but not infectious.

However, on the 2 hour long car ride home, this person went from infected to infectious and – with COVID19 being airborne and no one wearing masks – everyone in that car became infected.

We often say in medicine, timing is everything. It turns out, with rapid antigen tests and COVID-19, this still remains true.

09 January 2022

Writing Mysteries in the Age of COVID-19


As always, I’m curious on how to plot a murder mystery and have been peeking at how death investigations have changed.

Since COVID-19, mystery writers attempting to hide a murder have a different landscape to deal with. If a person is COVID-19 positive, even if they wouldn’t die from the disease - this is far more possible with the Omicron variant - a murder via poison at home would be easier to conceal.

Recently, our jurisdiction changed the rules stating, “Autopsies will no longer be performed on someone who is suspected to have died from COVID-19 unless there is another factor of great significance, such as a homicide.”

So, without evidence of blunt force trauma or anything obviously untoward, a murder via poison in a COVID-19 positive person can be more easily hidden.

Is this true in other jurisdictions?

“During the pandemic, many sick people have stayed at home and died there rather than seeking help at hospitals overwhelmed with coronavirus patients.

“In April in New York City, for example, a reported 200 residents died at home each day, compared with 20 such deaths before the pandemic…If family or friends say the person had symptoms consistent with COVID-19, the coroner's office will typically do a nasal swab to test for the virus, he says. If the test is positive and the office can determine the cause of death without an autopsy, one will generally not be performed.”

A review of the literature shows, “The literature is dominated by appeals for more autopsies to be performed…The main reason for the great reluctance worldwide to perform autopsies seems to be concerns about infectivity emanating from deceased persons.”

In the United States, there’s the added problem of cost, availability of specialists and the vast number COVID-19 deaths.

“Hospitals are not required to provide autopsy services, and in those that do perform them, the procedure’s costs are not directly covered by most private insurance or by Medicare…Added into the mix: The number of experts who can actually perform autopsies is critically low. Estimates suggest the U.S. has only a few hundred forensic pathologists but could use several thousand — and less than one in 100 graduating medical school students enters the profession each year.”

Add to this the fact that there are almost 860k COVID-19 deaths to date, the volume of detailed death investigations, let alone autopsies, of those who die out of hospital would overwhelm the system. So they are not done.

In hospital deaths are also not autopsied but with COVID-19 restrictions on visitors it would be hard to write a plausible mystery involving a murder in hospital.

So if autopsies aren’t done for most COVID-19 deaths, is toxicology conducted?

“How are forensic toxicology tests done? At the time of the autopsy, collection of blood, urine, and tissue samples is done in preparation for the toxicology tests, says Barbarajean Magnani, PhD, MD, chairwoman of the Toxicology Resource committee for the College of American Pathologists.”

So, given the concerns about infection from COVID-19 would collection of samples occur? I have not found evidence to suggest it is done.

While this certainly makes for intriguing options for writing mysteries, it’s a huge loss to science. Fulsome and numerous autopsies are the one crucial way to obtain information about a disease. For scientific purposes, more rather than fewer autopsies should be conducted. However, the limitations of time, personnel, well-ventilated facilities and PPE have limited autopsies and we have lost a great deal of data. Because of this, there’s been a pushback from many to perform more autopsies.

“The results from the analyzed studies show that autopsies are essential in the COVID-19 pandemic. They enable a more differentiated assessment of mortality. More important than the determination of the cause of death, however, is the fact that only the autopsy (including histological and virological examinations) opens up the possibility of investigating the spread of the virus in the body, the involvement of various organ systems, but also the late effects of the disease…

There are few valid reasons not to perform autopsies in COVID-19 deceased if the technical equipment meets certain minimum standards. It is easy to protect oneself against infection during the autopsy. Both clinical and forensic pathologists – preferably in cooperation – play an important role in gaining knowledge about the new disease as a basis for therapeutic measures and global pandemic control.”

I do wonder how mysteries written in the age of COVID-19 will be different because of the new landscape of death investigations.