The Journal Gazette
Tuesday, August 03, 2021 1:00 am

Adapt and survive

Christer Watson

Our path through this pandemic has taken another turn, unfortunately.

New CDC guidelines and news conferences about mask requirements are regular headlines. This change is entirely caused by our better understanding of the new version of the virus, called the delta variant. There is one study, led by scientists at the Massachusetts Department of Public Health, that has specifically changed our understanding. This change is a big deal.

Before the details, however, I want to highlight that this is what scientific progress looks like.

Our understanding is growing. As we gain understanding, the guidelines should change.

When I see public officials, such as school board members or, ahem, governors keeping the same rules, I stop trusting them. I worry they are not interested in using our best understanding to set the best rules for public health.

Back to the study. The setting is an unnamed town in Barnstable County, Massachusetts (think Cape Cod).Summer is high tourist season, with many public events. During July, there were 469 cases of the virus identified. This represented a large jump in cases compared with the recent past. The daily case rate (per 100,000) at the beginning of the month was zero. Two weeks later, the daily case rate was 177.

That represents a huge increase in a very short time. Nearly all these positive cases, 89%, were the delta variant.

Vaccination coverage for eligible Massachusetts residents is 69%. That is a relatively high value. Indiana, by comparison, is a little over 50%.

The scientists in this study were able to match the individual positive virus results against individual vaccination status, following the appropriate requirements for patient privacy.

They found that 74% of the positive virus cases, 346 people, were among those fully vaccinated.

The scientists performed a detailed analysis of some of these positive cases, both vaccinated and unvaccinated. They used a real-time PCR test that aims to measure the presence of genetic material from the virus from each person.

There are a range of types of PCR tests. Some PCR tests, which are more complicated, are designed to measure a range of virus levels. Other PCR tests, which are simpler, are designed just to measure whether the virus is above a specific level.

The difference here is somewhat like asking a person's age or asking whether they are older than 21.

The scientists found that among those positive cases from vaccinated people and unvaccinated people, the PCR tests were roughly the same. That is, for those positive virus cases, the amount of virus appeared the same, according to the PCR test.

This result is both shocking and requires a lot of caveats.

The result is shocking because much of the recent evidence implied vaccinated people were much less likely to spread the virus. This study may indicate that the delta variant is different.

Now the caveats. First, a majority of the positive cases were from people who were vaccinated. However, most people in Massachusetts are vaccinated. The bulk of the evidence, including earlier studies, still implies vaccines help tremendously against getting virus.

Just to repeat, you are less likely to acquire the virus, delta included, if you have the vaccine. This study does not provide enough evidence to change that important idea.

A second caveat: The PCR test was not set up to correctly measure a wide range of virus levels. In the metaphor, it was like asking whether a person is older than 21. Two people who answer yes may be the same age, or they may not. So scientists are uncertain whether the virus levels truly were equal between the two groups. Among both groups, it was high.

Based in part on this study, the Centers for Disease Control and Prevention has changed its recommendations. One reason is that we now believe the delta variant can spread among the vaccinated.

The most high-profile change in recommendations regards masks. Masks are recommended for indoor public places for everyone, vaccinated and unvaccinated. That includes schools.

The delta variant, based on this and other studies, also appears to spread more effectively than earlier versions of the virus. In the Massachusetts county, cases went from zero to 177 in two weeks. That is a remarkable, terrible rise.

We now have a better understanding of the virus, specifically this delta variant. Our public leaders, including school boards and governors, should be changing their recommendations based on this better understanding.

If we wait for everyone to understand these new results before changing policies, that will just give the virus more time to spread. True leadership here requires being ahead of everyone else.


Christer Watson, of Fort Wayne, is a visiting assistant professor of physics at Purdue University Fort Wayne. Opinions expressed are his own. He wrote this for The Journal Gazette, where his columns normally appear the first and third Tuesday of each month.

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