Stanford's Dr. Nirav Shah on Vaccines VS. Variants

Breaking news that virulent variants from Brazil, South Africa, and the UK are multiplying across borders even as homegrown strains are mutating on US soil, has raised a number of questions.

Are variants more contagious?
Will they cause worse infections?
Are current vaccines effective against mutating variants?
And should we take different precautions to keep safe?

Dr. Nirav Shah, MD, MPH, of Stanford University’s Clinical Excellence Research Center, fielded questions and concerns from ethnic media reporters at a press briefing on March 19. Along with other COVID 19 experts from the Bay Area, Dr. Shah shared information about new strains of the virus and safety net information for communities of color who want to sign up to get their vaccine shot.

“We cannot start to celebrate just yet,” said Shah, even though America reached an important milestone when the 100 millionth vaccine was administered on March 19.

The Story of Virus Variants

The emergence of variants has raised the specter that the current generation of vaccines might be rendered obsolete before they have even been fully rolled out. Are variants gaining ground and will they be immune to distinct vaccines before we reach herd immunity?

“It’s a race between how fast we get people fully vaccinated versus the level of disease in a community and how much transmission is going on,” explained Shah, about how a variant becomes dominant.

In heavily infected communities, the more virus particles there are, the greater the chance of one being different. All you need is a spike protein change, said Shah, which will give the variant a better chance of attaching to cells, so it spreads better and faster, becoming the dominant strain.

Simultaneously, as more people get vaccinated to combat COVID19, “the selective advantage of some particles relative to other particles, allow them to spread much faster.”

Now the race is on to get everyone vaccinated before the B.1.1.7. variant – the most dominant variant takes over.

“The story of virus variants is the story of evolution and natural selection,” added Shah.

Investigations of Variants

Currently, the CDC and WHO are studying the spread of three designated variants. Variants of interest -like the P2 which have ‘caused a cluster of infections’ in some countries, seem to be driving a surge in cases, though less is known about their transmissibility and lethality, or even if vaccine recipients are ‘fully neutralized against them or not’.

Their genetic sequence has some changes which suggest they may be more contagious, said Shah, and likely to be resistant to immunity bestowed by vaccines, treatments, or tests.

People are at greater risk from variants of concern that could reinfect survivors of certain Covid19 strains. Therapies and vaccines may be less effective against these strains which have “proven to be more contagious and cause more severe disease,” explained Shah.

Recent studies report that COVID-19 survivors and fully vaccinated people seem able to fight off infection from the virulent B.1.1.7 variant but may have less protection against the B.1.3.5.1 variant. Shah referred to research that shows the B.1.1.7 variant spreads about 50% faster and is more lethal, relative to prior strains of the virus.

The good news is that the existing range of vaccines (Pfizer, Moderna, Oxford/Astra Zeneca, and Novavax) have proven effective against this variant. But less is known about the transmissibility and lethality of the P1, B.1.4.2.7, and B.1.4.2.9 strains.

So far, however, assured Shah, no variants have met the definition for variants of high consequence which refer to strains that cause “more severe disease, more hospitalizations, and have been shown to defeat medical countermeasures” – like vaccines, anti-viral drugs, or monoclonal antibodies.

In the contest between vaccines and variants, “We will win the race by …vaccinating people as quickly…and broadly as possible” noted Shah.

An Annual Shot

Infectious disease experts liken variants to flu viruses which require new flu vaccines every year; scientists are even considering the possibility of multivalent vaccines designed to immunize against two or more strains of the virus.

“It’s a race of the mutant viruses against the vaccines…and to date, none of the mutants have escaped fully the major vaccines. The hope is that with minor modifications, we can get the continued evolution of the vaccines to match the evolution of the viruses.” It wouldn’t be surprising if the COVID vaccine was administered like a flu shot every year, added Shah.

Getting to Herd Immunity

The likelihood of reaching herd immunity will be a reality if at least 70% or more of the population are resistant to existing strains of the virus. However, as states relax public health restrictions as well as mask and social distancing mandates, herd immunity may be challenging to achieve. “More people getting infected simply means more chance of variants,” cautioned Shah.

I asked Dr. Shah if we would need a new generation of vaccines before the current vaccine roll is complete and if boosters would be introduced. “I am an optimist”, said Shah. “I imagine we would have booster shots by the fall but what’s important is that we all get that first shot, and make sure the vulnerable and elderly get theirs. That will make us collectively win”.

Dr. Shah reiterated that the Moderna, Pfizer, and Johnson & Johnson vaccines authorized by the Food and Drug Administration (FDA) for emergency use, are still the most powerful tools to fight all the strains of COVID-19.

“This is a race for the world,” said Dr. Nirav Shah. “We know the virus doesn’t respect any borders, and so we should be as broad as possible in our thinking about getting the vaccine to everyone across the world.”

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