With the emergence of new COVID-19 variants like the delta, as well as the lambda and B1-621 — both of which have been previously seen in parts of Central and South America — the pandemic continues to evolve.

Since COVID-19 first reared its head in China in the waning months of 2019, the virus has infected more than 212 million people across the globe, according to Johns Hopkins University. Globally, more than 4.4 million people have succumbed to the virus and its associated complications.

In the United States, there are have been more than 43.2 million cases of COVID-19 and more than 693,000 recorded deaths, as of Sept. 29. In Ohio, there have been 1.4 million confirmed COVID-19 infections and 21,945 deaths. According to the Ohio Department of Health, there are 64,451 hospitalizations related to the virus.

The delta variant has led to more than 3.2 million new diagnoses over the past month, with 18,254 related deaths in the last 28 days.

Ohio has seen thousands of cases of COVID-19 diagnoses each day throughout much of August. The Health Department reported that until August, there had not been a single day with more than 3,000 newly reported cases since February. Infection rates are rising in Ohio among the unvaccinated, as well as children who are not yet eligible for the vaccine.

In the United States, the delta variant is wreaking havoc on the unvaccinated. According to the U.S. Centers for Disease Control and Prevention (CDC), approximately 57% of the U.S. population has received at least one dose of the three that have been authorized or approved by the U.S. Food and Drug Administration, including the two two-jab vaccines developed by Modern and Pfizer and BioNTech, and the single dose regimen developed by Johnson & Johnson. Just less than half of the eligible population in the U.S., ages 12 and over, have been fully vaccinated, according to the CDC.

In Ohio, the percentage of vaccinated individuals lags behind the national average. The Ohio Health Department reports that 51% of eligible individuals have this far received the vaccine.

On Aug. 23, the FDA gave full approval to the vaccine developed by Pfizer and its Germany-based partner, BioNTech. Approval was granted to the vaccine, dubbed Comirnaty, for use in people ages 16 and above. The vaccine remains eligible for use in adolescents ages 12-15 under the FDA’s Emergency use Authorization.

Approval for the Pfizer vaccine, along with authorizations for the Moderna and J&J vaccines, was based on clinical trial data showing high levels of effectiveness. The two two-shot messenger RNA vaccines have higher levels of efficacy in the studies than the J&J version, but both were well-above the 50% efficacy threshold the FDA set in the early days of the pandemic.

As the virus has mutated, the three vaccines available in the United States have continued to demonstrate high levels of protection. With the emergence of the delta strain, twice as contagious as the other strains, according to the CDC, there have been so-called breakthrough cases, where vaccinated individuals are testing positive for the virus.

However, the vast majority of these individuals have been asymptomatic, or presented mild to moderate symptoms.

The FDA recently authorized a booster shot for the Pfizer and Moderna vaccines — six months after the second jab for individuals with compromised immune systems and eight months for everyone else. The reason for the boosters is a slight decline in efficacy after that period of time. While still effective in preventing severe disease and death, the decline in efficacy could allow new strains to increase the breakthrough infection rate.

That rise in delta infections sparked a change in CDC guidance regarding masks in July, even for the vaccinated. The CDC highly recommends the wearing of masks in areas where the infection rate is climbing, even among the vaccinated.

The updated guidance also reversed a previous decision and now calls for vaccinated individuals to get tested if they begin to show COVID-19 symptoms or following an exposure to the virus. The CDC says individuals should receive the test three to five days following exposure and take precautions to prevent potential spread among friends and family.