Not that we're even sailing yet ...

[Cruise Raider]

I just read a current article here on CC that outlines changes we may expect to see once cruising resumes.  I found the following excerpt in this article to be a bit baffling ... although, I have no degree in immunology, so maybe someone out there can explain this:  (please note that this is specific to Singapore so maybe others have nothing to worry about) 

 

The Singapore government prohibits anyone who has had COVID-19 within the past 180 days, or who has had a positive COVID-19 Serology certificate, from going on a cruise, as taking a pre-cruise SARS-CoV-2 (COVID-19) test could throw up a positive result, even if the person is no longer contagious. 

 

(please note that this is specific to Singapore so maybe others have nothing to worry about) 

 

Anyway, wouldn't a vaccine produce a positive serology result?  Isn't a serology test used to detect antibodies present in the blood post infection?  Wouldn't a vaccine also produce these same antibodies?  What am I not seeing here?  Hopefully there are some smart medical people here that can chime in.  

[JF - retired RRT]

3 minutes ago, Cruise Raider said:

Anyway, wouldn't a vaccine produce a positive serology result?  Isn't a serology test used to detect antibodies present in the blood post infection?  Wouldn't a vaccine also produce these same antibodies?  What am I not seeing here?  Hopefully there are some smart medical people here that can chime in.  

I think you're correct. Not absolutely positive, but I think so.

That's how you test to see if the vaccine worked.

[Cruise Raider]

5 minutes ago, JF - retired RRT said:

I think you're correct. Not absolutely positive, but I think so.

That's how you test to see if the vaccine worked.

 

That's what I assumed, too.  Hmmm?  Maybe the policy wasn't well thought out???  

[donaldsc]

3 hours ago, Cruise Raider said:

 

That's what I assumed, too.  Hmmm?  Maybe the policy wasn't well thought out???  

 

Totally ignoring the American political issues, have any of the Covid policies been well thought out or even thought out at all?

 

DON

[Cruise Raider]

2 minutes ago, donaldsc said:

 

Totally ignoring the American political issues, have any of the Covid policies been well thought out or even thought out at all?

 

DON

 

Maybe 'policy' was not the correct term to for me to use.  I am really just curious about the statement that a positive serology test, one that shows antibodies from a previous infection or a vaccine can preclude one from cruising for 6 months?  Isn't that what the cruiselines should want of their passengers and crew members?  I must just be missing something here ... 

[Ombud]

Now I'm confused. 😕 I understand the question just not Singapore's restriction 

Edited January 8, 2021 by Ombud

[gmjc2]

I think there may be a difference between the antibodies that show you have had the virus and the evidence of the vaccination. We had our vaccination yesterday so it will be interesting to see what shows up after the second dose in 4 weeks. 

[Shoalwater]

On 1/7/2021 at 10:23 AM, Cruise Raider said:

I just read a current article here on CC that outlines changes we may expect to see once cruising resumes.  I found the following excerpt in this article to be a bit baffling ... although, I have no degree in immunology, so maybe someone out there can explain this:  (please note that this is specific to Singapore so maybe others have nothing to worry about) 

 

The Singapore government prohibits anyone who has had COVID-19 within the past 180 days, or who has had a positive COVID-19 Serology certificate, from going on a cruise, as taking a pre-cruise SARS-CoV-2 (COVID-19) test could throw up a positive result, even if the person is no longer contagious. 

 

(please note that this is specific to Singapore so maybe others have nothing to worry about) 

 

Anyway, wouldn't a vaccine produce a positive serology result?  Isn't a serology test used to detect antibodies present in the blood post infection?  Wouldn't a vaccine also produce these same antibodies?  What am I not seeing here?  Hopefully there are some smart medical people here that can chime in.  

So this is a pandoras box.  Simply put, blood from COVID-19 patients with active infection will have bits of the virus RNA present for some variable length of time and as long as 1-2 weeks after they recover.  This RNA can be detected rapidly using a test called PCR, and is the basis for all the COVID-19 screening you read about.  Chances are that months after you are recovered, and certainly after receiving the Pfizer or Moderna vaccines you will not show a positive PCR result (there are false positives and negatives however).  Vaccines induce formation of neutralizing Anti-COVID-19 antibodies that bind to and inactivate the virus and prevent its transmission.  Natural infection can also induce antibodies, but these may have a different binding point from those caused by the vaccine. Telling the difference is not always easy.  In livestock disease many agricultural authorities in developing nations often conflate the presence of antibodies with disease and will destroy these animals much to dismay because most likely they are disease resistant.  It looks like the public health authorities in Singapore have used this broad brush to incorrectly interpret antibody presence with infectious disease potential, and simply decided to block anyone with a prior history of exposure to the virus or the vaccine.