Covid-19 infection on a liveaboard at the Maldives

[Oliver Ohlendorf]

Unless you are being unsafe in your home area, traveling to a new place via air absolutely increases your chances of getting infected - suggesting otherwise is downright silly.

So you never need to buy food, go to work or meet people otherwise?
Saying you are "safe" at home is simply silly.

Besides this most of the earlier reactions did not focus on the extra risk for the travellers but they tried to state that travelling imposes a risk for everybody else...

I guess that now we can return to the question if about who accepts the eventual extra risk.
And we can say that travelling does not add to the risk of others.

 

[Jcp2]

No I am not. How many percent of the population is currently actively infected? Around 10%? So assuming that you surely get infected, you need to meet 10 people and likely one will carry the virus - this is 10%. It does not take into consideration that you might avoid getting infected by preventional measures.

So let's say there are 100 people to get on the flight. The accuracy of the PCR test is above 90%. Out of the 100 passengers there are probably 10 to be infected. With 90% accuracy out of these 10 there will be only 1 not being detected. So out of the tested 100 passengers there is less than 1 probably sick. (1%) And this still does not account on the fact that you need to be in the proximity of that one infected person to get potentially sick.

Ro for Covid-19 is 2.2-5.6. So one infected person will cause 2.2-5.6 secondary infections in total.

More questions?

Your first example is a classic food poisoning probability question. Assuming that 10% of eggs carry salmonella, what is the chance of NOT catching salmonella when eating one egg? It is 0.9 (90%). What about after eating 10 eggs? It is 0.9 per egg, or 0.9 raised to the 10th power, which is 0.35 (35%). So your chance of catching salmonella (or in your example, meeting a person with coronavirus) is the inverse, or 65%. That is not 10%.

We can also play this game with the airplane, using test sensitivity, test specificity, and disease prevalence to derive positive and negative predictive values for people who get tested, and then load them onto an airplane. You've already stated disease prevalence as 10% and test sensitivity as 90%. I'll add in test specificity as 95%. This is a classic calculation, source below.

Positive and negative predictive values - Wikipedia

The positive predictive value for testing under your given scenario is 66%, so that for every 2 true positive test results there will be 1 false positive, and somebody either booted from the plane or quarantined without coronavirus. That sucks, but until the test sensitivity and specificity improves, or the prevalence of the disease goes up, it's

But for the people who actually get on the plane, we are interested in the negative predictive value. This works out to about 90%, so about 1 in 10 negative tests are actually infected with coronavirus. What is the chance that 100 people with a negative test that get on the plane are actually negative? It will be the egg problem, but with 0.9 raised to the 100th power. That's a very, very, very small number (0.003%), so it's essentially guaranteed that there is at least one, and likely closer to 10 people on the plane with coronavirus, even though everybody tested negative.

 

[ontdiver]

If you could explain me first what additional risk the LOB poses for everyone else (staying at home), please?
In my opinion moving from a region with many infections to a place where people got screened would also lower my chances to get infected, don't you agree?

With respect, I think your position is quite clear so I will leave you to carry on....

 

[Joneill]

So you never need to buy food, go to work or meet people otherwise?

• When I go to stores, I wear a mask as does everyone in the store. It is never crowded so I’m never in close proximity to anyone for more than a few seconds, if that. I’m in and out in 15 minutes or less. I sanitize my hands before getting in my car and wash when I get home.
  
• I’ve been working from home, like many others, due to COVID
• I have only met with people that are not my immediate family outdoors and we maintained social distancing. I have only done that rarely.

So... yes, sitting in an airport with thousands of strangers, right next to someone on a plane (for hours), and then living in close proximity to strangers on a who may be infected (PCR test is no guarantee tee) on a boat for a week... yup - that creates WAY more risk of getting and spreading COVID than my life at home.

 

[Oliver Ohlendorf]

Your first example is a classic food poisoning probability question. Assuming that 10% of eggs carry salmonella, what is the chance of NOT catching salmonella when eating one egg? It is 0.9 (90%). What about after eating 10 eggs? It is 0.9 per egg, or 0.9 raised to the 10th power, which is 0.35 (35%). So your chance of catching salmonella (or in your example, meeting a person with coronavirus) is the inverse, or 65%. That is not 10%.

We can also play this game with the airplane, using test sensitivity, test specificity, and disease prevalence to derive positive and negative predictive values for people who get tested, and then load them onto an airplane. You've already stated disease prevalence as 10% and test sensitivity as 90%. I'll add in test specificity as 95%. This is a classic calculation, source below.

Positive and negative predictive values - Wikipedia

The positive predictive value for testing under your given scenario is 66%, so that for every 2 true positive test results there will be 1 false positive, and somebody either booted from the plane or quarantined without coronavirus. That sucks, but until the test sensitivity and specificity improves, or the prevalence of the disease goes up, it's

But for the people who actually get on the plane, we are interested in the negative predictive value. This works out to about 90%, so about 1 in 10 negative tests are actually infected with coronavirus. What is the chance that 100 people with a negative test that get on the plane are actually negative? It will be the egg problem, but with 0.9 raised to the 100th power. That's a very, very, very small number (0.003%), so it's essentially guaranteed that there is at least one, and likely closer to 10 people on the plane with coronavirus, even though everybody tested negative.

So you mean variations?

I still think your calculation is faulty. Out of 100 passengers statistically without screening there are about 10 infected. The test can only produce a faulty result on 10% of these 10, all others are negative by default. That is clearly 1 to me. Also on the airplane I do not get in close contact with all the 100 passengers, only about 10 of them are in my proximity.

 

[Centrals]

Let us get things right! I do a PCR test so with a negative result the chance for me being infectious is smaller than average. This applies to most other travellers as well. I drive to the airport in my car meeting no one on the way. Inside the airport only travellers are allowed and most of them already belong to the screened group. I keep distance, everyone wears their masks and cleans hands regularly. On the plane there is a very good ventilation system that filters 99% of all infectious particles out of the air. As I explained earlier the statistical chance to get sick on an airplane is considerably low. At the Maldives the infection rates are considerably lower than in Europe so the chance to get sick is much lower. All people arriving to the LOB are screened, I am not sharing a cabin with any stranger (why should I?).

The "outings" are associated with socializing, avoidance of masks and social distancing.
When I go shopping everybody is touching the goods other people would probably buy, some people are too entitled to wear a mask.
Public transportation is plain and simply a mess. Nobody enforces distancing, wearing of masks and disinfection.

So yes, staying at home poses a bigger risk of getting sick and infecting more people around me.

On the other hand, travelling harms nobody else (just eventually me).
The chance to get infected abroad is simply smaller.

Absolutely non sense!!!
How many times you have been tested? Everyday or just once?

New Zealand's 1st new community COVID case in months is variant from South Africa

Who brought it to New Zealand?

 

[doctormike]

Let us get things right! I do a PCR test so with a negative result the chance for me being infectious is smaller than average. This applies to most other travellers as well. I drive to the airport in my car meeting no one on the way. Inside the airport only travellers are allowed and most of them already belong to the screened group. I keep distance, everyone wears their masks and cleans hands regularly. On the plane there is a very good ventilation system that filters 99% of all infectious particles out of the air. As I explained earlier the statistical chance to get sick on an airplane is considerably low. At the Maldives the infection rates are considerably lower than in Europe so the chance to get sick is much lower. All people arriving to the LOB are screened, I am not sharing a cabin with any stranger (why should I?).

The "outings" are associated with socializing, avoidance of masks and social distancing.
When I go shopping everybody is touching the goods other people would probably buy, some people are too entitled to wear a mask.
Public transportation is plain and simply a mess. Nobody enforces distancing, wearing of masks and disinfection.

So yes, staying at home poses a bigger risk of getting sick and infecting more people around me.

On the other hand, travelling harms nobody else (just eventually me).
The chance to get infected abroad is simply smaller.

OMG. We get it. You are traveling to go scuba diving, and you don't like being travel-shamed for it.

Not really interested in your ludicrous parsing of a fairly straightforward and near universal recommendation that people have been using to fight pandemics for centuries.

"Avoid unnecessary outings" means just what it says. You are coming up with ridiculous explanations about how "outings" implies no masks, but "dive travel" is safer than "outings" so that means that "dive travel" is exempt from the recommendations about limiting the motion of human beings around the planet.

I love diving. I hate missing out on dive travel this year. Too bad. I'm trying to #stopthespread, for all of the reasons that have been mentioned upthread.

 

[Oliver Ohlendorf]

Absolutely non sense!!!
How many times you have been tested? Everyday or just once?

New Zealand's 1st new community COVID case in months is variant from South Africa

Who brought it to New Zealand?

Hahaha. Now we are back to 0 and you are bringing an example where travel restrictions would have made sense: a country without any covid infections.
Yes this is the same as if travel would have been banned in 2019. Than it would really have made sense. But you know what? I did not want to visit HK anyway. And the Maldivians are awaiting my visit. So it is okay for me if you stay at home and keep posting...

 

[Fastnail]

Scientists are always careful about what they say but the evidence is plain. https://www.google.ie/amp/s/www.bbc.com/news/amp/health-55768627

There is enough peer-reviewed data and comment from the inventor of the PCR test to confirm that PCR tests are flawed when testing for infectious diseases (Coronaviruses).

 

[Oliver Ohlendorf]

There is enough peer-reviewed data and comment from the inventor of the PCR test to confirm that PCR tests are flawed when testing for infectious diseases (Coronaviruses).

WOW, again? You are mixing the PCR tests with rapid antibody tests, I guess.