Testing... testing... 1-2-3...

DEMAND AND SUPPLY - Boo Chanco - The Philippine Star

As the world attempts to get back to pre-pandemic normal, the question remains: how do we protect people from being infected in the course of daily life?

Vaccination is a good response, but not nearly good enough because even vaccinated people can get infected and pass on infection.

Our main problem is how to identify and isolate persons who are infected and able to pass on infection, but show no signs of infection. The scientific way of addressing the problem is proper testing.

But our Health secretary and our testing czar do not seem to realize there are two concepts at play: medical diagnostic testing and public health testing.

We have often heard the Health Secretary say that the gold standard test is the RT-PCR. As such, our health establishment has rejected all other tests as being less reliable.

However, there are experts who take a more nuanced view. Dr Michael Mina, an epidemiologist, physician and public health expert from the Harvard School of Public Health tweeted this view:

“Just because one technology is better for one thing doesn’t mean it is for all things.”

Dr. Mina offered a plan to get us out of this COVID war with no lockdowns, no waiting for vaccines, and reverse cases in weeks: rapid at home COVID tests.

He explained what rapid tests are in an interview with Slate, an online news magazine:

“Rapid antigen COVID tests are cheap to produce, easy to use, and can report results in a matter of minutes. They’re a powerful tool for stopping the spread of COVID because they allow people to test frequently, and if results are positive, quarantine immediately rather than wait one to five days for a PCR test result… for less than $1 per test, we could break the chain of transmission.”

The transmission window is short, rapid testing allows isolation when transmission is greatest, cutting off spread. But delays in PCR test results means it is a useless public health tool.

The Harvard specialist also points out that “If the goal is to detect people who are infectious, a rapid antigen test is highly sensitive and specific for this. PCR is not specific for this objective. It will read positive even when not infectious. So it is less accurate for the public health question: am I infectious?”

The benefit of testing, Dr Mina points out, whether it’s PCR or rapid testing, is frequency of the test. If you’re not doing a test frequently, you have no idea if you’re asymptomatically spreading.”

Accuracy is entirely dependent on what your objective is, Dr. Mina points out. “The conversation has been 100 percent dominated by physicians and clinical laboratory directors who are completely focused on medical diagnostics.

“And in a medical diagnostic, you’re not asking, ‘How are we going to stop spread across the community?’ You’re asking, ‘Does my patient have any evidence that they currently have COVID or did in the recent past?’

“But if our goal is instead to identify people who are currently transmitting the virus to other people, then actually the rapid test is much more accurate.

“The important thing is they’re specific, meaning they are only going to turn positive when you’re actually actively transmitting the virus. If the goal is to detect infectious people, then a rapid test is actually much more accurate, not less.”

The White House, in its latest COVID action plan, is recognizing the benefit of rapid tests. They will now require millions of Americans to vaccinate or test regularly.

Rapid tests were found to work very well in answering the question: Am I infectious and a risk to others? There are test kits that a person can use at home.

When our private business sector, through Joey Concepcion, brought up the possibility of doing rapid tests, the proposal was not given the attention it deserved.

It is a way to revive operations while protecting employees from infection. Even schools can safely reopen with rapid tests protecting teachers and students.

In the Makati Business Club paper that offered comprehensive suggestions, testing was once again placed on the table.

“We ask the government to study if and how testing can be improved. On speed, testing centers have needed to fill as many as 70 data fields per test. Reducing this to less than 10 may allow the testing centers to report faster to the LGU, allowing them to contact trace before more infection spreads.

“Data can be increased and improved by making more free or subsidized tests available or mandatory, including high quality antigen tests and incorporating private sector test data. This would give the government and public a clearer idea of the extent and rate of infection to help guide their actions. Like contact tracing, this may be more useful in helping keep infection levels low when we get there.

“At some point, it may be advisable to conduct survey-style testing to better estimate antibody/immunity levels in the population, not just those who choose to or have to be tested.”

Now with granular lockdowns, rapid tests in the affected areas will give a good picture of how badly the virus has penetrated the community. It is unfair to totally lockdown a barangay and deprive all residents of livelihood just because a few residents are infected and can be isolated.

Even Cebu Pacific announced they would require passengers to Hong Kong to undergo a rapid test just before boarding. That’s in addition to the PCR test taken three days before. They have to know if the passenger is infected at that very moment.

Past PCR-negative passengers tested positive upon arrival in Hong Kong. A three day old test isn’t very useful because infection could have happened after PCR testing.

Even Malacanang had long been conducting rapid tests on anyone attending a meeting with the President. With a number of Cabinet members catching the virus, the President could have been infected without rapid tests.

Rapid testing is probably the way of the future for countries eager to get back as close to normal as possible.

I imagine we are or should be.



Boo Chanco’s e-mail address is bchanco@gmail.com Follow him on Twitter @boochanco

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