Vaccination against the Delta variant: the newest COVID-19 research

The Delta variant has upended the decline in COVID-19 numbers, but the most recent scientific reports indicate vaccination continues to be dramatically effective against it.

The disease is changing with new variants, and the science is changing as more and more researchers report data reflecting the new dominance of the Delta variant. We reviewed the latest scientific studies, which reflect the presence of Delta. The general conclusions are:

❶ Delta is more capable of overcoming vaccination than Alpha or other variants.  That said, vaccination still provides remarkable protection—far more than half of vaccinated individuals will never experience illness with symptoms that make them feel sick.

❷ Vaccination will make you three times less likely to be infected than not being vaccinated. The COVID vaccines provide strong protection—better than the flu shot does against flu.

❸ Underlying medical conditions still increase the threat of severe infection requiring hospitalization, whether you are vaccinated or not, but vaccination improves your odds of experiencing few or no symptoms.

Here are some of the points in research published within the past three months. I have included hyperlinks so you can look at the original source material.

An Israel study showed that vaccination protection from the Pfizer vaccine dropped from 94 to 64 percent when measured against the Delta variant, the protection for the need for hospitalization only dropped from 97 to 93 percent. Meaning there was an increased chance you might get sick, but you were still extremely unlikely to get very sick. 

An India study similarly showed that while Delta gets through vaccination (which researchers call “breakthrough” infections) a little more effectively than other variants, most vaccinated individuals never get sick. 

An English study done from May to July 2021 found that during the study, earlier variants were completely replaced by Delta. And they found that unvaccinated people were three times more likely to get sick than the vaccinated. 

A Singapore study showed the mRNA vaccines, like Pfizer and Moderna, are extremely effective against the Delta variant. This study found that vaccinated patients who did experience breakthrough infections were much more likely to have no symptoms, while unvaccinated individuals were much more likely to get very sick. 

A Mayo Clinic study in the United States reviewed Moderna and Pfizer vaccines January through July 2021 confirmed that both were generally highly effective, but were less effective against Delta. That said, both are much more effective than the seasonal flu vaccine is against flu. 

A Canadian study found that all available vaccines provide significant protection against all variants. Single-dose vaccination provided some protection but full vaccination (2 doses properly timed) was far better. 

A BMJ (formerly British Medical Journal) article notes that vaccination provides good protection against infection, but that it provides excellent protection (in the 90+ percent range) against being so sick you need hospitalization. 

A Welsh-Scottish-Irish study found that vaccines provide similar or better protection than having actually had the disease. And even if you have had the disease, vaccination increases your protection against reinfection. “Effectiveness of two doses remains at least as great as protection afforded by prior natural infection,” the report says.  

The upshots are these:

Some vaccinated people will still get sick. That is the case with all vaccines--they are not 100 percent effective. As as case counts rise, you'll hear about more of these breakthrough infections, but that doesn't mean vaccines are not working.

All the newest evidence shows that vaccination makes you less likely to get infected with COVID-19, and that even if you do get infected, you are dramatically less likely be so sick that you’ll need hospital care.

Put another way, at this point in the pandemic, if you are not vaccinated,  you and your family are at dramatically higher risk of infection and severe illness.

© Jan TenBruggencate 2021