Disclaimer: This article was written in late July, 2021. Information may have changed since it’s publication date of September 10.
This article was written by Katie Ng and Jo-Anne Rivera.
The recent spike in the Delta strain, coupled with waning immunity among vaccinated individuals, has ignited debate regarding the need for a booster shot. Though those who are unvaccinated are at greater risk of falling ill, reports reveal that even vaccinated individuals are contracting and transmitting the virus at alarming rates. Booster shots have not yet been approved for the public but are an imminent possibility. To better prepare you for the next steps, we have collected information regarding the current status of the pandemic, as well as the potential rollout of the booster vaccine.
- What is a booster shot, and why do we need it?
A booster shot is a supplemental vaccine administered after the initial dose. Vaccines work by stimulating the formation of antibodies, but vaccinated individuals may lose protection against diseases as their antibodies weaken over time. By introducing modified antibodies to the immune system, a booster shot not only restores one’s immunological memory but also protects against new strains that may have developed resistance to the vaccine. Currently, boosters for the COVID-19 vaccine are not required, but both Pfizer and Moderna have begun to lead booster trials, especially in light of the Delta outbreak. Nonetheless, getting a third shot for vaccines is not uncommon, with many vaccines requiring at least three doses for full protection—especially for those who get vaccinated past childhood. This includes the Tetanus, Diphtheria, and Pertussis (Tdap) vaccine which is often given as a three-shot series for people seven years or older. Meanwhile, the HPV vaccine can vary in dosage based on one’s age, with older teens getting either two or three doses.
- Will everyone have to get a booster shot?
Currently, the trial booster shot is only accessible for vulnerable and immunocompromised individuals. Dr. Amanda Cohn, the Chief Medical Officer at the Center for Disease Control and Prevention (CDC) Immunizations Division, announced that the agency will distribute boosters to these populations first. However, research regarding the third shot is still in its preliminary stages. Dr. Anthony Fauci, the Director of the U.S. National Institute of Allergy and Infectious Diseases, says the advisory committee is still looking into its efficacy, so it is not yet being manufactured on a large scale. Despite the effectiveness of the current vaccines on the market, boosters will likely be necessary for everyone once different variants become more prevalent.
- How does the Delta variant differ from the original strain?
Due to its more transmissible nature, the Delta variant has become the dominant strain in the United States: it was responsible for 82.2% of COVID-19 infections in the beginning half of July 2021. This can be attributed to the variant’s several mutations. Compared to the original strain’s incubation period of six days, these genetic changes have decreased the variant’s incubation period to four days, causing infected individuals to become contagious sooner. With this, individuals infected with the Delta variant are capable of transmitting the virus to six people on average. On the other hand, individuals with the original strain would only infect an average of two to three people. Regardless of the lethality of the variant, its high transmission rate alone is competent enough to afflict large masses—especially potential hyperlocal outbreaks. Nonetheless, the symptoms of the Delta variant are generally similar to the previous COVID-19 strains, such as fever, chills, fatigue, muscle or body aches, difficulty breathing, nausea or vomiting, etc.
Instead, certain symptoms that were common for the past strains are absent in these Delta cases, most notably, the loss of smell and taste.
The Delta variant is being transmitted in more than 90 countries, notably the United Kingdom, the United States, and India. In terms of the United States, as of July 15, the five states with the lowest vaccination rates include Alabama, Arkansas, Louisiana, Mississippi, and Wyoming. The hospitalization rate and the trajectory of new cases in these areas are significantly higher than the states with the highest vaccination rates.
- Should vaccinated individuals be concerned?
The New England Journal of Medicine reported that the Pfizer vaccine is 93.7% effective against the Alpha variant and 88.0% effective against the Delta variant, suggesting that the original two doses continue to provide modest protection against hospitalizations and death. However, it is still possible to contract and transmit the virus, given the 2.9 times lower susceptibility to neutralization compared to the Wuhan strain. Vaccinated individuals do not need to be concerned about the booster shot, but everyone should exercise caution to avoid another outbreak.
- Are companies working towards manufacturing booster shots already?
In response to waning immunity among vaccinated individuals in Israel, Pfizer has launched clinical trials to test the efficacy of a third shot. At the company’s Second Quarter Teleconference held on July 28, 2021, researchers reported that the third dose resulted in five to eleven times more antibodies against the Delta strain as compared to the second dose. In their study, the third dose was administered more than six months after the second. The Moderna trial administers a booster to individuals who were vaccinated for at least 12 weeks. However, the study does not restrict its scope to Moderna boosters on Moderna vaccines. Each cohort represents a different vaccine that individuals received, and the booster is administered to all, allowing researchers to observe the effects and efficacy of “mixing” vaccines. Johnson & Johnson’s Single-Dose COVID-19 Vaccine is still being administered, but there is little information regarding its lifespan in the immune system or the potential of a booster. Furthermore, Pfizer has developed one batch of a new Delta-specific vaccine, and its clinical studies will begin in August 2021.
- When will the booster shot become available?
None of the three approved vaccines (Pfizer, Moderna, Johnson & Johnson) have administered booster shots beyond their clinical trials, but Pfizer expects to submit an Emergency Use Authorization (EUA) application for their formula as early as August 2021. Moderna has not released information regarding when to expect rollout for their booster. - How often will I need to take the booster shot?
Though it is not yet clear how often booster shots are required (and whether they are necessary at all), schedules from other vaccines suggest that boosters are usually administered every several years. Tdap boosters, for example, are required every 10 years. Meanwhile, meningococcal boosters are encouraged more frequently, as their antibody count depletes much more quickly (between one to five years). Another relevant case is the yearly flu shot, which involves new vaccines that are specific to the season’s dominant strain. There is not enough data to conclude how the COVID-19 vaccine will be administered in the future, but Pfizer and Moderna have announced fully vaccinated individuals are protected for “at least six months after the second dose.” Depending on how efficiently the virus mutates, boosters may be regularly administered from anywhere between months to years.
- How should we protect ourselves and others against the Delta variant?
Given the more lenient social distancing restrictions coupled with the resurging infection rate, one of the best ways to be protected is getting vaccinated. However, as of July 30, the CDC’s mask guidance has changed upon a new study showing that fully vaccinated people are capable of spreading the Delta variant. Among the 469 COVID-19 cases in Provincetown, Massachusetts, three-quarters were attributed to fully vaccinated people. This find prompted the CDC to change its mask guidance, recommending fully vaccinated people to wear masks in high and substantial transmission areas. Meanwhile, unvaccinated people must continue to wear masks in all areas.
The outbreak referenced in the CDC’s decisive study has since been contained, as tweeted by Alex Morse, the town manager of Provincetown. “Of the 900 cases related to the Provincetown cluster, there have been no deaths, 7 hospitalizations, and the symptoms are largely mild,” Morse added.
Although the transmission rate amongst vaccinated individuals is concerning, the original vaccines remain highly effective against the virus. Despite how these vaccines do not necessarily prevent infection, they help mitigate its severity, hospitalizations, and death. By wearing your mask—vaccinated or not—you are helping to slow the spread while also keeping yourself safe.
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