The difference? Prompt and ongoing access to medical care.

The onset of the COVID-19 pandemic led to a dramatic drop in health care utilization across settings and specialties. Elective surgeries were canceled. ER utilization for non-COVID care decreased. Retail health centers and urgent cares closed. And many patients, heeding the guidance to shelter in place, did without outpatient primary care. This has led to concern among health care professionals. According to a recent survey, 60% of primary care physicians said they were worried that delayed primary care will lead to preventable illnesses.

As a result, many primary care practices quickly adapted, successfully offering virtual care for issues such as mental health services and even chronic disease management.

But patient uptake has been variable across the country. Patients don't always have reliable internet connections, especially in rural and lower-income communities. They are often unaware of, or still don't have access to, virtual primary care services.

In a recent survey, nearly half of Americans reported they have skipped or delayed medical care during the pandemic.  And, as many patients have opted to delay or forgo primary care, some practices have been forced to permanently close.

The overall long-term health consequences of this pandemic are yet to be determined and will likely be varied. But here is a refrain I tell my patients and colleagues: Primary care is an essential service.

Evidence tells us that delaying primary care will have detrimental effects. Mortality rates are lower in regions with more primary care physicians. For every 10 additional primary care doctors per 100,000 people, life expectancy increases by 51.5 days.

This is due, in part, to chronic disease management. Uncontrolled diabetes and hypertension can lead to stroke and heart attack. Poor asthma and COPD control can lead to exacerbations. Many of these chronic diseases can increase the severity of COVID-19, especially when uncontrolled.

We are already seeing that vaccination rates for children have dropped since the start of the pandemic, raising concerns about potential outbreaks at the onset of the school year this fall. The drop is seen among all childhood vaccines, including measles.

Patients are also skipping out on screening labs, some of which are time-sensitive and critical. For example, missing asymptomatic or presymptomatic STD cases ranging from chlamydia to HIV infection risks further spread. Even more concerning: missing an opportunity to talk with a primary care physician about sexual health.

And, of course, ignoring acute symptoms, such as pain, could lead to potentially preventable ER visits.

Mental health is another important part of primary care. With depression and anxiety on the rise and suicide rates the highest they have been since World War II, it's vital that patients continue to have access to mental health services.

But a peculiar phenomenon could arise from a world with less medical care: Are there any areas where we will actually see better outcomes?

It likely depends on the type of care. Delaying certain procedures, which may have been unnecessary in the first place, could lead to similar (if not better) outcomes. H. Gilbert Welch, M.D., M.P.H., and Vinay Prasad, M.D., M.P.H., have written about the important concept of "less is more" in medicine. Certainly, delaying cancer screenings will lead to missed diagnoses. What remains to be seen are the outcomes of delayed cancer diagnoses that were in early versus late stages.

But high-quality primary care delivery is actually designed around the concept of high-value care: ensuring the right patients get the right services at the right time.

So, I will continue to repeat my refrain: Primary care is not elective. It is essential.

Natasha Bhuyan, MD, is a board-certified family physician in Phoenix. You can follow her on Twitter @NatashaBhuyan.