Are the vaccines effective against new variants?


A: Signs point to YES.

While some emerging SARS-CoV-2 variants are more concerning than others, so far the vaccines remain effective at preventing disease and death.

💥 This means that while new “scariants” may make for eye-catching headlines, vaccines are still doing what we hoped to save lives and ultimately drive down transmission.

Because of the frequent replication of the virus, small genetic changes over time are normal and expected. By chance some of these changes may help the virus transmit more easily or evade some of our immune responses.

Luckily our immune systems are clever and mount a multi-pronged defense that makes it hard for variants to fully evade vaccine-induced immunity. These defenses include polyclonal antibodies and T-cells that cover many different parts of the spike protein.

The vaccines in many cases are proving to be SO good that even when neutralizing activity is diminished by a new variant, baseline levels were so high levels that the vaccine can still easily neutralize the virus- in other words the vaccines have plenty of headroom to work with.

We can test vaccine effectiveness to new variants in several ways:

➡️ Laboratory studies that test whether blood from vaccinated people can neutralize the virus in a dish.
➡️ Real world evidence comparing vaccinated & unvaccinated people where variants are circulating.
➡️ For some vaccines, we also have clinical trial data that can be examined by variant (Novavax, J&J, Astrazeneca)

Based on all of this evidence, here’s the TL;DR about key variants of concern (also see attached summary table from Dr. Eric Topol):

🇬🇧 B.1.1.7: Good neutralization and highly effective against infection and disease
🇿🇦 B.1.351: Some loss of neutralizing ability but good protection against infection and severe disease
🇧🇷 P1: Some loss of neutralizing ability but good protection against infection and severe disease
🇮🇳 B.1.617: Effective against infection and disease

Some recent data highlights:

💥 In Qatar, the Pfizer vaccine was 100% effective in preventing severe disease or death from variant B.1.1.7 and B.1.351. It also showed 89.5% effectiveness against B.1.1.7 infection and 75% effectiveness against B.1.351

💥 Moderna released preliminary data from its Phase II trial of booster shots. A single dose of its original vaccine given as a 3rd dose increased neutralizing antibodies against B.1.351 and the P1 variant. A booster containing the B.1.351 variant achieved even higher antibodies against B.1.351 than the original vaccine booster.

💥 Data from the lab of microbiologist Dr. Ravi Gupta suggest that the so-called “double mutant” B.1.617 variant does NOT show substantial immune evasion after one dose of the Pfizer vaccine.

➡️ The vaccines are working, even against emerging variants.
➡️ Variants still introduce uncertainty into the pandemic so continuing to stamp them out is crucial.
➡️ The faster we vaccinate the world, the more lives we can save and the less opportunity for variants to arise.

Those Nerdy Girls

Further Reading:

Table compiled by Dr. Eric Topol

“Effectiveness of the BNT162b2 Covid-19 Vaccine against the B.1.1.7 and B.1.351 Variants”

“Pfizer COVID vaccine protects against worrying coronavirus variants”

“What are the India, Brazil, South Africa and UK variants?”

“Moderna says Covid booster shot generates promising immune response against variants found in South Africa, Brazil”

Gupta Lab results

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