How Bad Will the Summer Delta Wave Be?

By Robert L. Moore, MD, MPH, MBA, Chief Medical Officer

“Don’t accept the world as it is. Dream of what the world could be – and then help make it happen.”

-Peter Tatchell

For the past year, for some reason I have enjoyed playing some Pandemic-related games with my sequestered family. The best is Pandemic Legacy: Season 1, a cooperative game where players work together to save the world from dangerous pathogens, including some that turn people into virtual zombies. It is a long game, taking many days to complete. I’m happy to say that my family saved the world twice, although many people died and some cities were destroyed in the process.

An older computer game (from 2008) called Pandemic 2 takes a different perspective, where you are the microbe and you are trying to kill as many people as possible. Not surprisingly, perhaps, the best way to do well in this game is to know how COVID-19 unfolded, with asymptomatic respiratory spread, followed by mutations that increase infectiousness and subvert the effectiveness of vaccines. This really helps hit home what is currently happening with the Delta variant.

Recent estimates put the R0 more infectious Delta variant of COVID-19 at six to eight, compared to the R0 of the original Wuhan strain, which was estimated at 2.7. (Reminder: the R0 represents the average number of contacts infected by a single infected person.) This translates to 80-90% of the entire population (including children) would need to have good immunity to this strain to prevent a wave.

While the vaccination rate among California adults is 61.4%, only 51.8% of California’s entire population has been fully vaccinated against COVID-19. Of the 12% of the partially vaccinated, some may have had prior COVID infection before vaccination, in which case the single dose is probably about as effective as two doses in a person who never had COVID; the remaining individuals with a single dose have about 34% protection. Overall an additional 8% protection rate is reasonable. From seroprevalence studies, around 15% of the remaining 36% have been previously infected against COVID, but not vaccinated. Unfortunately, prior infection with non-Delta strains confers only about 30% protection against Delta, so the effective rate of protective immunity is only about 65% in our state, far from the now-needed 80-90%, hence the current exponential growth of infection against the Delta variant.

As of last week, the California Department of Public Health (CDPH) projected that the 2021 summer delta wave will be a little less severe than last summer’s COVID-19 wave. Based on the experience in the similarly-vaccinated United Kingdom, which is about 1 month ahead of us in the Delta wave, the hospitalization rate will be about 1/3 of what we experienced in prior waves. This means the risk of overwhelming the hospitals and ICU capacity of the state is low, so dramatic stay at home orders or restaurant closures are less likely to be needed or considered.

The upshot: this will likely be a quicker, steeper wave, with hospitalizations and deaths concentrated in the smaller, unvaccinated population. The rates of infection in the unvaccinated population will likely equal the overall infection rates we saw this past winter.

The vaccinated population is considering the recommendations of local public health officers to encourage wearing masks in indoor settings when among strangers, to slow down their lower-morbidity spread of the Delta variant. By itself, this will have a small impact on the overall epidemic curve. It may protect them and their families in the month ahead.

Vaccination is our best hope for fighting this particular virus, with its combination of high infectiousness, high level of asymptomatic spread, and relatively rapid development of mutations that help it evade our immunological and public health defenses—a lesson confirmed by two games written before COVID-19 struck.

You play a key role in this real-life game. Thanks for dedicating yourself to this vision of a better world.

Statin Therapy Lagging in Patients with Cardiovascular Disease or Diabetes

By Robert L. Moore, MD, MPH, MBA, Chief Medical Officer

Most of us forget the basics and wonder why the specifics don’t work.

-Garrison Wynn

In 2019, about 40% of PHC members with diabetes were not being prescribed recommended cholesterol-lowering medications. For patients with diagnosed cardiovascular disease, about 20% had not received statin therapy.

Statin therapy prescriptions and patient adherence to prescribed statin treatment are NCQA HEDIS measures that we will be focusing on in the years ahead. We urge clinician leaders to look at the rates of prescriptions in your practice and remind clinicians of the importance of prescribing statins in these two groups. If you can, set alerts in your Electronic Health Record system (EHRs) to remind clinicians to consider this therapy.

Clinical Background:
Cardiovascular disease is the leading cause of death in the United States. Patients with clinical Atherosclerotic Cardiovascular Disease (ASCVD) are at high risk for future cardiovascular events, including myocardial infarction, stroke, and death from Cardiovascular Disease (CVD). Lipid abnormalities are also common in patients with diabetes, and contribute to an increased risk for developing ASCVD. The American College of Cardiology and American Heart Association (ACC/AHA) as well as the American Diabetes Association (ADA) recommend statin therapy to prevent cardiovascular disease and reduce ASCVD risk.

Summary of Recommendations:
Therapy to reduce the risk of subsequent cardiovascular events includes addressing modifiable risk factors such as smoking, hypertension, diabetes, and elevated levels of low-density lipoprotein cholesterol (LDL-C). The ACC/AHA guidelines state that statins of high intensity or maximally tolerated statin doses are recommended for adults age 75 or under with established clinical ASCVD regardless of the baseline LDL-C. A maximally tolerated statin dose should be used to reduce LDL-C levels by 50% or more.

In patients with diabetes (but without clinical ASCVD), the ADA and the 2019 ACC/AHA guidelines recommend statins for primary prevention of cardiovascular disease, based on age and other risk factors. Moderate-intensity statin therapy can be initiated without calculating a 10-year ASCVD risk. For patients with diabetes who are at higher risk, especially those with multiple ASCVD risk factors or aged 50 to 70 years, high-intensity statin therapy should be considered to reduce the LDL-C level by 50% or more. Consideration may be given for addition of a SGLT-2 inhibitor or GLP-1 receptor agonist with proven CVD benefit to improve glycemic control and reduce CVD risk in patients at higher risk.

The HEDIS Measures
The HEDIS measure Statin Therapy for Patients with Cardiovascular Disease assesses the percentage of males 21–75 years of age and females 40–75 years of age with clinical ASCVD who have received and adhered to statin therapy.
The HEDIS measure Statin Therapy for Patients with Diabetes assesses the percentage of adults 40-75 years of age who do not have diagnosed ASCVD.

Best Practices
Here is a summary of best practices for adding appropriate statin therapy and improving adherence for patients with diabetes and/or cardiovascular disease:

  1. Review medication list to confirm a statin has been prescribed when indicated.
  2. Provide patient education: explaining goals of statin therapy and need for adherence.
  3. Prescribe statins as 90 day supplies, once therapy is stable.
  4. Ask your patients open-ended questions to monitor for adverse drug reactions, drug-drug interactions, and other obstacles that may hinder medication adherence.
  5. Collaborate with dispensing pharmacies to identify and address medication adherence gaps.
  6. Specific medication recommendations:
    1. For high intensity statin therapy (lowers LDL-C by >50%), consider atorvastatin 40-80 mg or rosuvastatin 20-40 mg.
    2. For moderate intensity statin therapy (lowers LDL-C by 30% to <50%), consider atorvastatin 10-20 mg, rosuvastatin 5-10 mg, or simvastatin 20-40 mg.

Thanks for passing this along to your front line clinicians.