‘Tis the Season for Colds, Flu, and COVID

Staying healthy for the next six months or so is more difficult because of three commonly spread viral diseases. (See Figure 1.)By now all the readers of this column know about COVID which has not yet settled into the seasonal rhythm that the common cold and influenza have. Readers also know that the elderly are in a high risk group when it comes to these diseases. 

Causes

The cold, influenza, and COVID are all three caused by viruses. The cold is usually a result of infection with the rhinovirus; influenza is mostly caused by the Influenza A or B virus; and COVID results from infection with the SARS-CoV-2 virus which, like the influenza viruses, now has many variants. The variants now ravaging the U.S. are the Omicron BA.4 and BA.5. All of these viruses are spread mainly by particles expelled from infected people to the uninfected who then breathe them in. The common cold and influenza can also be spread by touching surfaces that infected people have contaminated with shed viruses. All three virus are easily spread by close contact and physical touching. 

Most Vulnerable People

The main reason we are writing about these communicable diseases in this healthy aging column is that these common viruses pose higher risk to elderly people. Data from infections with all three viruses now show the viruses cause more harm to older people. In fact, the risk that complications may occur increases with each additional year of age. This begins at age 50 and peaks after 80. In other words, the older you are, the more the potential for complications and adverse outcomes increases. COVID is still considered the most deadly of the three illnesses and the common cold the least severe.

In addition certain groups of people are more vulnerable, particularly to flu and COVID. People unvaccinated against the flu and COVID are at significantly greater risk for complications from the infections than those who are vaccinated. People over 65 who received full vaccination with either the Pfizer or Moderna vaccines have a 94% lower risk of COVID hospitalization! People who have immune-deficiency disorders, asthma, heart disease, diabetes, and lung disease are susceptible to complications from influenza and COVID. The viruses can cause pneumonia and other respiratory-system problems that require hospitalization, sometimes with artificial/mechanical breathing, and death. 

Symptoms

I suspect everyone has had the common cold and knows quite well what the symptoms are. A cold usually lasts a week to 10 days and it is best to stay home or away from crowds so as not infect others during the first two to three days. The symptoms from influenza appear one to three days after infection and last only five to seven days. COVID causes symptoms within two to three days of infection and usually subsides in one to two weeks. People who have influenza and COVID are infectious (can spread the disease) for up to a week and approximately 10 days, respectively. The symptoms for each disease are listed in Table 1. There are a large number of symptoms for all three diseases and most of the symptoms occur to varying degrees in each of the three.

Diagnosis

From the overlap of the symptoms, it is clear that the diagnosis is not easy and we use what we in medicine call a “high index of suspicion” to make the diagnosis. This means if you have been exposed to someone who has a known virus or it is very prevalent in the community, it is likely you have that disease (cold, flu, or COVID). There is no test to diagnose the common cold, but influenza and COVID can be identified by tests that involve nasal swabs. One of the major accomplishments in the COVID pandemic was the ability to very accurately test for the COVID virus using an antigen or antibody test. Now rapid tests are available to all Medicare recipients for at-home use (See Figure 2). If you do contract influenza or COVID, it is recommended by the CDC that you quarantine for five days from the time you test positive or have symptoms.

Prevention and Treatment

Prevention is always the best strategy in the coming virus season. Stay away from people known to be infected; wear a mask if you must be exposed to someone who is sick; keep rooms well ventilated; spend as much time as possible around people as possible in outdoors venues; and wash hands frequently. Vaccines exist for influenza and COVID. Although the vaccines do not prevent getting the diseases, they have been proven to reduce the severity of the disease and significantly reduce hospitalization and death from influenza and COVID. Everyone in our age group should be vaccinated unless there is a medical reason not to. Beginning in October it will be possible to be vaccinated for COVID and influenza at the same time.

Supportive treatment for all three infections involves staying hydrated, rest, analgesics for pain, and isolation from others. Additionally, antiviral medications may be prescribed for certain patients who have influenza or COVID. The medical decision obviously depends on your status and the recommendations of your physician. If antiviral medicines are to be used, then it is best to intervene as early (within two days) as possible in the disease process.

The Bottom Line

We are approaching the annual time when endemic viral diseases (that have been here all along) begin to emerge. We have learned from COVID how to protect ourselves and prevent serious illness and fortunately the things we do to prevent COVID are effective against the common cold and influenza. Beginning this month vaccines are available for both the flu and COVID. Get them!

Illustrations

Table

SYMPTOM	COLD	INFLUENZA	COVID
Symptom onset	Gradual	Abrupt	Abrupt
Fever	Rare	Common	Common
Aches	Unusual	Common	Common
Chills	Uncommon	Fairly common	Fairly common
Fatigue, weakness	Uncommon	Usual	Very common
Sneezing	Common	Sometimes	Common
Cough	Mild to moderate	Common	Very common
Runny nose	Common	Sometimes	Very common
Sore throat	Common	Sometimes	Common
Headache	Rare	Common	Common
Change in taste	Rare	Sometimes	Common

Figure 1

Average seasonal activity of influenza in the U.S. From the CDC.

Figure 2

The two lines indicate a COVID-positive home test. From the author's recent bout with COVID.