CDC COVIDView Week 15

#15,201

During the regular influenza season we often take a look at the CDC's weekly FluView Report, which tracks influenza and ILI activity, hospitalizations, and laboratory results in the United States.

In a similar format, the CDC now produces a weekly COVIDView report.

Now that influenza activity has fallen markedly (see CDC FluView Chart  below), most of the ILI (Influenza-Like-Illness) being reported around the country can be assumed to be COVID-19 related. There are, of course, still a few flu cases even during the off season, and later this summer we'll be on watch again for our biannual resurgence of EV-D68. 

From the latest ILI maps (see below), it is apparent that COVID-19 isn't affecting the nation equally, with only a few states reporting very high rates during week 15. 

Even so, the next chart - depicting the P&I (Pneumonia & Influenza) Mortality is the highest I've seen in 14+ years of writing this blog, dwarfing the the numbers we saw during the 2017-2018 high severity flu season and during the 2009 H1N1 pandemic. 

*Data during recent weeks are incomplete because of the lag in time between when the death occurred and when the death certificate is completed, submitted to NCHS and processed for reporting purposes.

P&I data is always a lagging indicator, since deaths usually occur late in an illness, often after weeks of hospitalization or treatment. There are also other delays in reporting, meaning that this week's spike likely represents cases infected in mid-to-late March. 

While we've seen changes in the way data has been collected and collated with the P&I report over the years - making direct comparisons difficult - this is another indication (as if we needed one) that COVID-19 produces more severe outcomes than does seasonal influenza. 

Some excerpts from this week's report, but follow the link to read the report in its entirety.

Updated April 17, 2020

Download Weekly Summary pdf icon[10 Pages, 2 MB]

Key Updates for Week 15, ending April 11, 2020

This CDC report provides a weekly summary and interpretation of key indicators that have been adapted to track the COVID-19 pandemic in the United States. While influenza-like illness (ILI) declined, it is still elevated and laboratory confirmed COVID-19 activity continues to increase as do COVID-19 severity indicators (hospitalizations and deaths).

Virus

Public Health, Commercial and Clinical Laboratories

Public health, commercial and clinical laboratories are all testing for SARS-CoV-2, the virus that causes COVID-19, and reporting their results. The national percentage of respiratory specimens testing positive for SARS-CoV-2 increased from week 14 to week 15 and is as follows:

• Public health laboratories – increased from 17.3% during week 14 to 17.8% during week 15;
• Clinical laboratories – increased from 10.6% during week 14 to 11.5% during week 15;
• Commercial laboratories – increased from 20.6% during week 14 to 22.6% during week 15.

Outpatient and Emergency Department Visits

Outpatient Influenza-Like Illness Network (ILINet) and National Syndromic Surveillance Program (NSSP)

Two indicators from existing surveillance systems are being monitored to track outpatient or emergency department (ED) visits for potential COVID-19 illness.

• Nationally, the percentages of visits for influenza-like illness (ILI) and COVID-19-like illness (CLI) are elevated but decreased compared to last week.

Recent changes in health care seeking behavior are likely impacting data from both networks, making it difficult to draw further conclusions at this time. Tracking these systems moving forward will give additional insight into illness related to COVID-19.

Severe Disease

Hospitalizations

Cumulative COVID-19-associated hospitalization rates since March 1, 2020, are updated weekly. The overall cumulative hospitalization rate is 20.0 per 100,000, with the highest rates in persons 65 years and older (63.8 per 100,000) and 50-64 years (32.8 per 100,000).

Mortality

Based on death certificate data, the percentage of deaths attributed to COVID-19, pneumonia or influenza increased from 17.8% during week 14 to 18.8% during week 15.
All data are preliminary and may change as more reports are received.

A description of the surveillance systems summarized in COVIDView, including methodology and detailed descriptions of each data component, is available on the surveillance methods page. 

Key Points

• CDC has modified existing surveillance systems, many used to track influenza and other respiratory viruses annually, to track COVID-19.
• Nationally, the percentage of laboratory specimens testing positive for SARS-CoV-2 continued to increase.
• Visits to outpatient providers and emergency departments (EDs) for illnesses with symptoms consistent with COVID-19 are elevated compared to what is normally seen at this time of year but decreased compared to levels reported last week. At this time, there is little influenza virus circulation. The levels of people presenting for care with these symptoms is likely due to COVID-19 but may be tempered by a number of factors including less ILI overall because of widespread adoption of social distancing efforts and changes in healthcare seeking behavior.
• The overall cumulative COVID-19 associated hospitalization rate is 20.0 per 100,000, with the highest rates in persons 65 years and older (63.8 per 100,000) and 50-64 years (32.8 per 100,000). Hospitalization rates for COVID-19 in older people are higher than what is typically seen early in a flu season.
• Based on death certificate data, the percentage of deaths attributed to COVID-19, pneumonia or influenza increased from 17.8% during week 14 to 18.8% during week 15.

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