Veil of uncertainty

When the Ministry of Health reported its negative test results for a COVID-19-positive Bahamian passenger on board one of last week’s repatriation flights from Florida, questions and skepticism immediately arose in the public domain.

The Ministry’s assertion that “health officials are satisfied that the passenger did not pose a risk to other passengers traveling on the same aircraft”, casts a veil of uncertainty over this process because the ministry provided no pertinent data to support this determination.

If the ministry is positing via this assertion that it considers the passenger’s initial positive test result to have been a false positive and hence no risk existed to other passengers, it must produce the data to support this.

On Sunday, Prime Minister and Interim Minister of Health Dr. Hubert Minnis advised that all returning Bahamians must have “a molecular COVID-19 test performed with a negative result”.

The ministry did not indicate which molecular test the passenger submitted to in the United States, be it the “gold standard” RT-PCR test administered worldwide and in The Bahamas, or rapid molecular tests, which are not as accurate as the RT-PCR.

If the passenger’s test taken abroad was the RT-PCR test, this test has an over 90 percent specificity and sensitivity rate — meaning it is difficult to yield a false positive from this form of testing.

The reason comes down to the diagnostic properties of the test.

COVID-19 is an RNA virus; the kind of virus that infects a host (in this case, human beings) by injecting RNA into a host cell in order to replicate, and the RT-PCR tests for COVID-19 are designed to yield a positive result only when the virus’ converted RNA is present.

Though it is difficult to yield a false positive from the RT-PCR test, the likelihood of getting a false negative increases depending on how samples are collected.

If the nasal swab method is used, as is done in The Bahamas, and the test swab is not inserted far enough into the nasal cavity, an insufficient amount of test specimen could be collected, which could result in a false negative of someone who is COVID-19-positive.

A study published in March by the Journal of American Medical Association (JAMA) indicated that only 63 percent of those who were positive for COVID-19 tested positive using the nasal swab method for the RT-PCR test.

The ministry did not indicate whether the passenger’s test was taken at a facility where the tests of other returning Bahamians were conducted.

But, if it in fact doubts the passenger’s positive test result, whether from a RT-PCR or a rapid molecular test, what is its position on the accuracy of any of the negative test results which have been reported?

Outside of the ministry discounting the passenger’s COVID-19-positive test result, what would have otherwise informed its conclusion that the previously COVID-19-positive passenger presented no risk to other passengers?

Research findings vary on how long a person with COVID-19 continues to shed the virus, and the ministry’s tests appear to have been taken within the 14-day window of mandatory quarantine for those diagnosed with the disease.

Additionally, the ministry would not know what the passenger’s level of interaction was with other passengers, and no information was provided on whether the passenger was symptomatic nor what kind of face shield he traveled in, given that cloth masks do not provide the same level of protection against viral shedding from the nose and mouth as do properly-fitted surgical and N95 masks.

No information was given, meantime, on the test results of the persons with whom the passenger traveled.

It is important that full disclosure in this matter is not viewed as merely an academic exercise, because public skepticism is rooted in suspicion that the latest turn of events are designed to lift weight off those responsible for the breach of protocol, which resulted in the COVID-19 passenger being permitted to board last week’s repatriation flight.

The minister of health, who first brought to the nation’s attention the existence of a COVID-19-positive passenger on one of the flights, must present to the Bahamian people all the facts associated with his ministry’s statement in the interest of public trust, and in the interest of his public health team.

Once all the facts are known, the Bahamian people can better determine how and if they wish to move past the current veil of uncertainty.

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