With the summer upon us, Americans are anxious to get back to pre-COVID-19 normal in order to gather with friends and family, attend events in person, and travel again. While some states have completely reopened, one city in Michigan reports one in three citizens testing positive for COVID-19, while India is experiencing a substantial wave of new cases.
When considering infectious diseases, it is probable that different regions of the country or the world have different concurrent experiences when confronting COVID-19. This same pattern happens with other outbreaks, including influenza, where one section of the country has significant illness while another simmers. What conditions must be present to induce disease from an infectious agent?
Conditions for Infectious Disease
Patient-specific risk factors, pathogen characteristics, and environmental conditions are necessary to cause infection. Let’s take a look at each of these factors.
It is important to consider the individual’s susceptibility to the pathogen. Older patients and those with underlying medical conditions are particularly susceptible to COVID-19. Other patient risk factors include genetics, where some patients respond to COVID-19 with an overwhelming inflammatory response, which may be responsible for much of the severe illness.
COVID-19 is quite virulent, where other pathogens may only cause disease if they have the opportunity. Inoculum plays a significant role, i.e., briefly passing a COVID-19 positive individual while jogging is less risky than standing in a room with a critically ill COVID-19 patient.
A region with an active outbreak is very different from one that has little disease. Weather may be a factor. For instance, influenza is quite responsive to changes in weather patterns. Historically, coronavirus has also been temperature-responsive, with previous outbreaks fading in warmer weather. In addition, herd immunity may alter the environment, but that process takes time and may be affected by the emergence of variants.
Public Health Interventions
When considering public health interventions, epidemiologists use the above outbreak-specific risk factors as well as the following four domains related to the intervention:
- What is the risk of the intervention?
- Is the intervention feasible?
- What is the cost of the intervention?
- Is the intervention effective?
Let’s look at the current strategies for combatting the spread of COVID-19.
Wearing masks does not carry high risk. It is feasible. The cost is low, but efficacy is variable. In some situations, the efficacy may be irrelevant. For example, wearing a mask in a COVID-19 unit will be highly effective in preventing disease, but wearing a mask while jogging by yourself in a public park is probably unnecessary. This rationale is why the CDC changed mask requirements for vaccinated individuals, because host susceptibility is so low that the efficacy of the mask intervention is too low to consider.
Shutdowns of businesses, schools, restaurants, churches, etc. is very costly, not feasible in the long run, and is very risky to an individual’s well-being. While shutdowns are effective at preventing the spread of disease, the overall cost is painful.
There is some risk to the vaccine with regard to immediate feelings of illness, as well as rare side effects. While a mass vaccination campaign is difficult, it is completely feasible. The cost is not high compared to other interventions, and the efficacy is incredibly high. COVID-19 vaccination stands today as the most powerful intervention.
Is COVID-19 Over?
Before the vaccines were available, we could control COVID-19 spread only through masking, hand washing, and shutdowns. In light of the risk factors for infection, these strategies only affect the inoculum an individual may receive without fundamentally modifying patient-specific risk factors or the overall environment. These strategies essentially help people avoid the disease.
Is COVID-19 over? No, but we can continue to advance the strategy of vaccinations to keep the positive momentum going. Vaccination fundamentally alters patient risk, pathogen virulence, and environmental conditions.
So, while COVID-19 is not over, we in the United States are able to reopen carefully while continuing to increase the number of people who are vaccinated.
For more information, please visit CPSpharm.com.