The Delta Variant: A Guide To Evaluating Personal Risk

(Posted on Wednesday, August 11, 2021)

As the Delta variant spreads rapidly across the United States, fueling Covid-19-related hospitalizations in regions with low vaccination rates, Americans remain unsure of the effect this highly infectious mutant will have on their lives. While vaccines reportedly prevent critical illness and death in those who received them, stories of deadly breakthrough infections in individuals of all ages are causing a stir, leading some to speculate that vaccine-mediated immune protection might not be as strong or last as long as previously hoped.

To be clear, any protection is better than no protection, so mass immunizations should and must continue. But the growing dominance of Delta, which is significantly more contagious than previous strains of SARS-CoV-2, does demand we reconsider our current approach to situational awareness and safety. These adjustments required needn’t be undertaken in panic or confusion. The onus to reinstate basic safety measures remains on government and health officials, but individuals can take steps on their own to determine their personal risk level and act accordingly.

The question on the minds of many is simple: if I’m vaccinated, am I still protected? But the answer is much more complicated. Even the best of the current generation of Covid-19 vaccines, the mRNA vaccines created by Pfizer and Moderna, don’t erect an impenetrable barrier between the body and the virus. Instead they trigger an immune response that teaches the body to recognize and neutralize the virus on sight. If the virus mutates beyond immune recognition, then the vaccine loses all or most of its potency, hence the recently popularized term “vaccine-busting variant.”

Here are some practical considerations we can make as we await more clarity and guidance on variants to come.

Here are some practical considerations we can make as we await more clarity and guidance on variants to come. First, as long as new variants continue to appear, get comfortable with maintaining some level of situational awareness. What are infection rates like in your neighborhood? What about the communities of people you interact with on a daily basis? The higher the prevalence, presumably, the higher your personal risk.

Second, remember that “Covid-21” is not the same as Covid-19. The Delta variant appears to be up to ten times as infectious as the parent SARS-CoV-2 strain that originated in Wuhan. It also appears to efficiently infect people of all ages, including teens and young children, in some cases causing critical illness and even death. This means the basic safety measures we relied on for the better part of 2020 to protect ourselves—mask wearing, handwashing, social distancing—only go so far. Even people who followed CDC guidelines religiously for the past 18 months may find themselves infected. So long as our public health controls aren’t as aggressive as the virus itself, it will fall to individuals to exercise caution than before.

Third, reevaluate and upgrade your mask wearing and social distancing habits. Until we know how proficient non-clinical grade masks are at protecting against the new variants, I recommend wearing an N95 mask when meeting with anyone outside your immediate bubble, whether indoors or outdoors. I also recommend avoiding large groups of people even outside and limiting indoor exposure to as few people in as short a time as possible. Remember that the Delta variant is so contagious, Australian health officials have documented transmission through “fleeting” non-physical contact in cafes and shopping malls.

But what of vaccination status? This brings me to my fourth and final point: if you’re vaccinated, do what you can to monitor your personal level of immune protection. This involves two main variables. First, your concentration of anti-SARS-CoV-2 antibodies. Two kinds of antibodies, which are similar but not identical, have been established as adequate correlates of immune protection from Covid-19: those that bind to the spike protein and those that inhibit it. The latter, also known as neutralizing antibodies, have the tightest correlation, but spike protein antibodies are a reasonable surrogate. 

A combination of clinical safety and efficacy data and computational modeling studies shows that the higher your antibody titer, the higher your likely level of protection. Different vaccines elicit different antibody titers, with the mRNA vaccines generating the highest. My recommendation is, beginning two weeks after vaccination, to get tested for antibody count and have the same test—no standardized assay is available yet—repeated every four months. Your antibody titer will give you a rough approximation of your protection from infection.

The second variable is time. In addition to your antibody count, which is determined in large part by the type of vaccine you received, monitoring how much time has passed since your last shot can also help you estimate your level of protection. According to one study, vaccine-generated antibodies can wane as much as 50 percent in as few as 10 weeks. All anti-SARS-CoV-2 antibodies fade, but how quickly they fade depends on your age and medical history. This is why some countries are in the process of making booster shots available to older adults, whose immune responses tend not to be as vigorous or long-lasting.

No magic number of antibodies or anything else can guarantee immunity against existing and future variants of SARS-CoV-2. But it’s time we accept the reality that with a highly contagious variant on the loose, the chances of someone who is vaccinated falling ill and dying are inevitably higher. At least 100 individuals were lost to such circumstances in Massachusetts, according to a new report. Studies also show that the Delta variant generates higher viral loads in our nasal passages, irrespective of vaccination status, increasing opportunities for transmission.

To circle back to where we started, if protection is likely to falter or fade, is it worth getting vaccinated in the first place? Absolutely yes—on this question I’ve no equivocation. But only with vigilance around situational awareness, the threat presented by new SARS-CoV-2 variants, and the strength and length of our antibody titers can we ensure we’re protecting ourselves and each other to the best of our ability.

All in all, we have to up our game when it comes to countering and defending ourselves against more infectious and dangerous forms of the Covid-19 virus. If our governments and local health officials won’t intervene, we need to take responsibility for our individual actions and behaviors to minimize risk to ourselves and the people around us. Over time we can end this pandemic through more broadly protective vaccines, prophylactic drugs, and rigorous public health measures. But until these reinforcements materialize, we need to keep our collective guard up, or risk letting everything we’ve built up to ensure our recovery fall apart.

Read full article on Forbes

Originally published on Forbes (August 11, 2021)