New federal guidance on masking and testing highlighted an eventful week in the COVID-19 response, as government authorities work to respond to the rising transmission of the Delta variant.
CDC Updates Masking and Testing Guidance for the Vaccinated
On Tuesday, July 27, the Centers for Disease Control and Prevention (CDC) updated its guidance on masks. The agency now recommends that certain Americans, including those vaccinated living in areas with substantial or high transmission rates, wear masks indoors. The agency also advises those individuals to get tested after a suspected or confirmed exposure to COVID-19. If found to be COVID-19 positive, they are recommended to quarantine for 10 days. The agency is also following the lead of the American Academy of Pediatrics by recommending that children wear masks in school settings this fall. In May, the CDC issued guidance stating fully vaccinated individuals — apart from workers in health care settings, correctional facilities, and homeless shelters — do not need to wear a mask nor physically distance indoors. Tuesday’s action, which was in response to the increasing transmission of the Delta variant, updates this previous May guidance. In the CDC’s announcement this week, the agency indicated that preliminary data suggest fully vaccinated individuals infected with the Delta variant can spread the virus to others.
New Policy for Federal Employees
On Thursday, July 29, the Biden administration announced a new requirement for all federal employees and onsite contractors to attest to their vaccination status or practice masking and social distancing protocol and be subject to frequent testing. Due to the new CDC guidance, those federal employees who are vaccinated but live in an area with substantial or high transmission rates will have to wear a mask indoors. The guidance does not provide a timeline of how or when the new rule must be implemented, nor does it explain any consequence of not complying. In addition, the Department of Veterans Affairs this week announced mandated vaccinations for their health care workers.
Vaccine Booster Shots
One m-RNA vaccine manufacturer announced it will seek authorization for a third booster shot following their Wednesday announcement of data showing its vaccine's effectiveness against symptomatic COVID-19 dips from about 96% to 84% after six months. The company said they will submit the data for a booster by mid-August. Also this week, President Biden indicated the Food and Drug Administration (FDA) will look to provide full approval in early fall for COVID-19 vaccines that are currently authorized under emergency use authorization.
Relaxing Non-Pharmaceutical Methods Too Early Predicted To Increase Chances of Resistant Strain
A study published in Nature Scientific Reports looked at how the rate of vaccination and the use of non-pharmaceutical methods to reduce viral transmission impacted the creation and dominance of resistant viral strains in a population. The researchers created a model resembling SARS-CoV-2 transmission and found that a high vaccination rate lowers the chances a resistant strain will emerge. However, their modeling also demonstrated that relaxing or removing non-pharmaceutical countermeasures — such as masks, social distancing, quarantine of infected individuals, etc. — has a direct correlation to an increased probability that a resistant strain will be established in a population. Without controlling the transmission of the virus to a point that the mutant strains will not have a sufficient pool of individuals to infect, mutant strains are a possibility. The researchers concluded that maintaining diligence of non-pharmaceutical measures and other transmission-reducing activities through the entire vaccination process is the best strategy to prevent the emergence of new resistant strains. Otherwise, vaccine researchers will need to continue modifying vaccines to combat these new variants when the current vaccines lose efficacy.
Available Blood Tests Do Not Predict Individual Level of Protection Against COVID-19
In general, both prior vaccination and prior infection offer protection against COVID-19, as has been demonstrated based on numerous studies and real-world evidence amassing data from millions of people. But predicting protection for a particular person is harder. A blood test that could tell exactly how much protection a given individual has would be very useful. However, research and technical development in this area remains a work in progress, and no available blood assay can answer that question. Part of the difficulty lies in our still-imperfect understanding of the human immune system, which has many complex and interrelated components. It remains unclear which particular component or combination of components the blood tests should be evaluating in order to provide values correlating with protection against COVID-19. Additionally, normal immune responses change over time so that antibodies may naturally fade over a few months — but longer-term memory immune cells could still provide protection. There are no standard tests, let alone standard “threshold” values, to allow predictions about protection. Blood readings from different people may vary widely yet be indicative of similar protection, or conversely be similar yet mean different protection outcomes (see, for example, Figures 2 and 3 in this recent study) depending on individual biology, as well as time from the event that triggered the immune response. To complicate matters further, some types of antibodies isolated from the blood of recovered patients seem to enhance (instead of fight) infection in the Petri dish — although not in full organisms. The ultimate difficulty lies with the mutating virus, since new variants may avoid the immune defenses developed in response to past infections or vaccinations.
Gargle to Your Health!
Non-pharmaceutical interventions (NPI) — such as masking and hand-washing — have served to tamper down the spread of COVID-19 before vaccination became available (to adults). For the kids returning to school this fall, vaccination may still be not an option, so NPIs would be important to keep everyone safe. One of such ways to strengthen the barrier to infection is gargling. It might be a skill worth teaching even to young kids, along with teaching them teeth-brushing and hand-washing. Gargling tap water works well, and doing so with a 1% aqueous solution of povidone iodine might work even better to prevent a SARS-CoV-2 infection.
Details of the SARS-CoV-2 Attack, Step-by-Step
The story of the SARS-CoV-2 action at the molecular and cellular level is still being written. By now, many steps have been clarified in minute detail, from the spike protein’s conformational (shape) change to its surprisingly efficient invasion of the host (human) cell. Other details still need to be sorted out — such as the ways in which viral proteins shut down the host cell’s own processes and redirect them to manufacture exclusively the components that would assemble into new viral particles, or the ways in which the virus silences the infected cell’s signals to the immune system. These ongoing investigations give us a better understanding of SARS-CoV-2, including its newer variants, and help identify critical steps and molecules in the SARS-CoV-2 lifecycle that could be targeted by future drugs.
What’s in a Name?
We have been witnesses to the debates around the naming of SARS-CoV-2 and its numerous variants (called alpha through lambda by now). Curiously, the word “virus” itself apparently comes from the Latin word for “venom of a snake,” or “poison.” Records of human afflictions caused by viruses go back more than two millennia, although their causative agents were not understood until many centuries later. Remarkably, first vaccines against viral diseases were developed in the 18th century, well before the true nature of a virus was elucidated — which began with scientific discoveries in the late 19th century.