A Phantom Surge

Dr. Rochelle Walensky represents the much-touted “return to competence” embodying the science-driven approach of the Biden administration to COVID-19, in contrast with the Trump administration’s incompetent ignoring of scientific principles.

This week, Dr. Walensky issued a serious warning at her press conference. The steady decline in cases that the US has seen since mid-January has been halted, and, in fact, reversed. “The most recent seven day average of cases, 66,000, is an increase of 3.5% from the prior seven days.” This alarming trend was cited by Dr. Walensky, on Friday, as the reason that the CDC is delaying its release of new guidelines for vaccinated people — guidelines that some commentators think are important to encourage more people to be vaccinated.

The CDC seems to be worried that the collapse in cases happening all across the US has been stalled due to the spread of variants that some scientists believe are more transmissible and even might be impervious to the immunity afforded by the vaccine or by previous COVID-19 infections. Seeing cases tick up, Dr. Walensky is encouraging us to be careful and certainly, not to engage in Neanderthal thinking.

A quick look at the numbers shows that she’s not wrong. During the seven days ending on February 14, the US tracked 94,000 cases per day. Then, during the week ending on February 21, the daily average was 69,300 cases per day! But that plunge was arrested during the week ending February 28. Cases were actually up slightly, to 69,600 cases per day.

But the consequences of the COVID-19 restrictions that have been imposed on the world are massive enough that we should not urge people to be careful just on the basis of a quick look. The vaccine could serve as a psychological inflection point. People have been terrified of the virus and committed to helping society by “staying home”. For these people, the vaccine could have been the time of transition, freeing them to resume their lives. The CDC and the public health community, more broadly, have been pumping the breaks. They have put up all kinds of arguments for why and the new “surge” is just the latest. So we should take more than a quick look.

Dr. Walensky’s words contain an astounding observation. She continued, “The most recent seven day average of deaths also increased 2.2% from the previous seven days to now slightly more than 2,000 deaths per day.”

Wait, what? Anyone that is following COVID-19 statistics from the earliest days of the pandemic knows that deaths lag cases by 2–4 weeks. Remember when Mike Pence said “Fatalities are declining all across the country” in June and we all laughed grimly because we knew that the deaths would follow?

Since deaths lag cases, it can’t possibly be true that the US is experiencing the beginning of a new surge in cases and, simultaneously, a new surge in deaths. That’s just impossible. If a new variant and relaxed restrictions were causing more people in the US to be infected with COVID-19, we would expect to see an increase in deaths in 2–4 weeks. How can there be a death surge and a cases surge that start at the same time?

Fortunately, the mystery isn’t very difficult to solve. During the week ending on February 21, many public health offices were closed, first for Presidents Day on February 15, then because of the severe weather that affected much of the country. So, the dramatic dip in cases (a 35% drop in seven days) was not a reflection of so great a decrease in actual infections. Rather, it reflected a dip in the number of cases reported to the CDC. Then, during the week ending February 28, the backlog of infections began to come in. So the reported numbers show a huge drop from Feb. 14 to Feb. 21, then a slight uptick from Feb. 21 to Feb. 28, both in cases and in deaths. But what was actually happening was a steady drop in cases and deaths, of about 15–20% per week — roughly the same pace as the previous four weeks of drops.

We don’t have to wonder whether this explanation is plausible, because the exact same pattern has played itself out during each holiday. Memorial Day, July 4th, Labor Day, Thanksgiving, Christmas/New Years and MLK Day — for each of these holidays, there is a dip during the week of the holiday and an increase in the two weeks after the holiday.

The two graphs below are from Worldometers. It’s easy to see the dips on the holidays, followed by the surge after the holiday. The line is the seven day average, which smooths out the differences in reporting between days of the week.

The dips are easiest to see when cases were high and surging, and a bit harder to see when cases were low or dropping.

On the deaths chart, the dips are easier to see, because the scale is much smaller, so the dips show up better. There are also dips in cases for all these holidays. But, because of the scale on the chart, they are not easy to see. They can easily be verified at the site

On the charts, you can clearly see that the real surges in cases — early March, mid June and early October — precede the surges in deaths — late March, early July and late October. But both cases and deaths have the dip and surge pattern around holidays, because they are not real, they are just artifacts of the reporting.

So the head of the CDC is scare-mongering. She is claiming that the data show a surge, when the data don’t show the surge. The only question left to answer is whether she knows that there are no such data and is just claiming that there is an uptick as a sort of “pious fraud” or she just doesn’t understand enough about the data.

As COVID-19 cases and deaths drop all around the country, people look to the CDC for guidance on when to relax the restrictions that impose immense social and economic costs on our society. If the head of the CDC cannot read the data properly, or if she can read the data but chooses not to tell the country the truth, we should probably stop listening to the head of the CDC.