Is COVID 19 Vaccine Effective Against DELTA VARIANT? - Doctor Mike Hansen
Is COVID 19 Vaccine Effective Against DELTA VARIANT?
COVID 19 Vaccine breakthrough cases are popping up in the news.
Is the delta variant responsible for breakthrough infections?
Do the vaccines still work?
COVID 19 cases, hospitalizations, and deaths are on the rise again. Right now, there are 162 million Americans who are fully vaccinated. According to the CDC, less than two percent of people hospitalized with COVID 19 are vaccinated. And get this - 99.5% of people who die of COVID 19 did not get the vaccine.
A COVID 19 breakthrough infection is defined as someone who tests positive for COVID 19, with a PCR test, at least 14 days after being fully vaccinated. Several reports of breakthrough infections have been reported at the White House, Congress, Olympics, Major League Baseball, and more. I’ve seen people with breakthrough infections in the ICU, but not nearly as much as COVID 19 patients in the ICU who did not get the vaccine.
Stanford is among nearly 600 universities and colleges nationwide that have required students and faculty to be vaccinated against COVID 19 before coming back to campus this fall. Stanford 7 Vaccinated Students Get Symptomatic COVID 19 in a week span.
Even before the delta variant showed up, we knew that the vaccines aren’t 100% effective. Based on the original studies, we knew that the mRNA vaccines with Pfizer and Moderna were about 95% effective at preventing severe COVID 19 illness. This means that percentage is even smaller when you’re talking about preventing mild or asymptomatic infections. But the important thing you want to know is how effective the vaccine is at preventing severe COVID 19 illness.
But that 95% effectiveness was based on the original strain of COVID 19. Now, the scarier and more contagious Delta variant makes just about all the COVID 19 cases in the US.
According to this recent study, when people are infected with Delta, they have about 1000 times more viruses than previous versions of the virus. So all that viral load has the potential to overwhelm the immune system of vaccinated people. Another study that was just published in the NEJM also showed that the delta variant is slightly more likely to cause breakthrough infections:
Researchers found that after two doses of the Pfizer vaccine, it gave 88% protection against symptomatic disease caused by the delta variant, and that’s compared to 93% against the alpha variant that was first discovered in the UK.
Both doses of the AstraZeneca vaccine offered 67% protection against symptomatic disease. We’re still waiting on published numbers for the Moderna vaccine, but according to the company, its vaccine remained effective against the different variants.
The Johnson & Johnson vaccine might be less effective against the Delta and Lambda variants, but that study is yet to be published. It might be that those who received the J&J vaccine may need to get Pfizer or Moderna to protect against the new variants. So stay tuned on that.
We know that those vaccinated have milder Covid 19 illness compared to unvaccinated if they become infected if they do become infected. This is based on another study published in the NEJM that looked at more than 3,900 essential workers. It shows that fully vaccinated people are more than 90% protected against infection. Even partially vaccinated people are 81% less likely to become infected than people who haven't had been inoculated.
Vaccinated people appear to be less likely to spread the virus to others. Those who got "breakthrough" infections after one or two doses of vaccine had 40% less virus in their bodies and were 58% less likely to have fever. They spent two fewer days in bed compared to unvaccinated Covid 19 patients.
Then there is the question, if you’re asymptomatic and have been vaccinated, can you still spread the virus to others? We know the vaccine reduces the likelihood of carrying the virus. And if you are carrying the virus, we know that there would otherwise be a reduced viral load. So overall, its less likely that you are transmitting the virus if you’re asymptomatic and you’ve been vaccinated. This is why the CDC says that fully vaccinated people still need to be tested if they have symptoms and shouldn't be out in public for at least 10 days after a positive test. This is actually being studied right now in 12,000 college students who received the Moderna vaccine.
And what about those of you who are vaccinated, and you are concerned about getting a breakthrough infection? If you were to get COVID 19, it's way more likely to be a milder course of the disease if you are exposed to many people, especially if they’re not vaccinated; you can wear a mask. The kind of mask to wear is another topic, but even a regular face covering would still be better at decreasing transmission compared to no mask at all.
Doctor Mike Hansen, MD
Internal Medicine | Pulmonary Disease | Critical Care Medicine
= new reply since forum marked as read
"herd immunity", "break-through" joins the list. 
When it comes to COVID-19, there is no such thing as "herd immunity" and thankfully that phrase is slowly but surely being removed from the lexicon.
Similarly the term, "break-through" is stupid because this vaccine is NOT a complete "shield" to infection. Whether you are vaccinated or not, you CAN get infected, and spread it. The difference is how ill you might get from it IF infected based on whether you are vaccinated or not.
This is no different from the flu shot, where you can still get the flu, particularly if you end up catching a strain that wasn't accounted for in what is usually a trivalent or quadrivalent vaccine mix. But in many cases, the duration of your infection will still be reduced because your body might be able to adapt faster if the variant, although not exact, is at least close to what was in the vaccine.
Yet despite that well-known fact, the medical and scientific community continues to fuel what has become a convoluted media message that is trying to encourage people to get vaccinated so they don't die or end up in the hospital, yet makes it seem like if you did get the vaccine, you're "home free" and can go "back to normal", with any future infection being "extremely rare". That's bullshit and is disingenuous messaging.
It's sad that we are really in a dire situation with this thing and trying to balance the messaging without excessive hyperbole or excessive dismissal, is difficult at best.
There are some pathogens with vaccines that are pretty close to being 100% effective, and it's most likely due to their not mutating much if at all. But COVID-19 is NOT one of those.
