COVID-19 Weekly Newsletter: CDC Expands Booster Recommendation

As 2022 gets underway, public health agencies have been busy updating guidelines and working to expand vaccine access as health care providers and researchers contend with the now-dominant Omicron variant.

‘Flurona’ Case Identified in the U.S.

The first United States case of “flurona,” a term used to characterize when an individual tests positive for flu and COVID-19 at the same time, was identified this week in Los Angeles. Another case was identified in Israel. While contracting both conditions simultaneously is believed to be rare, this is not a new diagnosis given that these two diseases are caused by distinct viruses. As early as January 2020, co-infections were detected in 58 of 19,256 cases studied in the United Kingdom. Flu vaccination rates are low and COVID-19 cases up by over 200% compared to two weeks ago. As health care systems throughout the world are strained due to the pandemic, health officials continue to urge vaccination against COVID-19 and the flu along with other mitigation strategies of social distancing, frequent hand washing, wearing masks, and opening windows and doors for ventilation.

CDC Expands Booster for Teens

On January 5, Centers for Disease Control and Prevention (CDC) Director Rochelle Walensky endorsed the CDC advisory panel’s recommendation for teens ages 12 to 17 to be eligible to get a booster dose of the mRNA vaccine. This new recommendation followed the Food and Drug Administration’s January 3 decision to authorize boosters for younger adolescents. CDC’s external advisory committee, the Advisory Committee on Immunization Practices (ACIP), voted 13-1 for the new teen booster recommendation. The main point of debate was whether this new recommendation was the best approach to mitigate the pandemic’s effects given the number of unvaccinated people.

FDA Shortens Interval To Get mRNA-based Vaccine Booster by One Month

On January 7, the FDA shortened the mRNA vaccines’ booster interval between the completion of the primary two-shot series and a booster for adults to at least five months, one month short of the previous recommendation of six months. This update impacts anyone 12 or older who completed their mRNA-vaccine dosing regimen.

CDC Isolation and Quarantine Guidelines

On December 29, the CDC updated its isolation and quarantine guidelines. According to the latest guidelines, individuals who test positive for COVID-19 and whose symptoms are resolved only need to isolate for five days — as long as they continue to wear a mask for an additional five days. For individuals exposed to the virus who are unvaccinated or are not yet boosted, the CDC recommended that they quarantine for five days and wear masks for another five days. For those boosted, they can return to work after exposure but should wear a mask for 10 days. As defined by CDC, “isolation” means separating sick people with a contagious disease from people who are not sick; “quarantine” means separating and restricting movement of people who were exposed to a contagious disease to see if they become sick.

Uncertainty Remains Regarding Post-Infection Protection Levels

Prior to the emergence of the Omicron variant, research found that mRNA vaccines provided a greater level of protection against COVID-19 than the protection provided by a prior SARS-CoV-2 infection — a finding that many found surprising. With the emergence of newer viral variants as well as the time-dependent contraction of immunity elicited by the original vaccinations or infections, the question about the breadth and durability of immunity afforded by vaccines, booster shots and previous COVID-19 infections has been put on the research agenda once again. Editors of the New England Journal of Medicine discussed the difficulties associated with such research — in part because current tests cannot distinguish between prior infections and reinfections — in this interview recorded on December 14, 2021.

Fully Vaccinated Population Less Contagious — Even if Infected

A recent study from Germany analyzed data on SARS-CoV-2 infections from December 2020 through August 2021, when vaccines were widely available there. The study showed that COVID-19 cases were almost ten times more frequent in the unvaccinated. Moreover, the vaccinated and subsequently infected with SARS-CoV-2 individuals were less infectious to their contacts than the unvaccinated. That study did not analyze genetic sequencies of the infecting virus, however.  Another study conducted in the U.K. suggested that, unlike for an earlier Alpha variant, infections with Delta were associated with a high viral load and, therefore, infectiousness, regardless of the vaccination status.

Omicron Outstripped All Other Variants in the U.S. by Mid-December 2021

In the United States, the Omicron variant was first detected in late November 2021. As of December 18, 2021, over 73% of SARS-CoV-2 infections were due to the Omicron variant. By January 1, 2022, that proportion rose to over 95%.

A study of neutralizing antibodies in plasma showed that a previous SARS-CoV-2 infection or vaccination offered only a weak protection against Omicron, while a booster restored immune system’s capacity to fight off Omicron.

Oral Pills for Mild or Moderate COVID-19

On December 23, the FDA granted emergency use authorization (EUA) to two oral pills that help prevent the progression of mild or moderate COVID-19 cases to severe disease. Both drugs are only available by prescription, and both must be taken within five days of symptom’s onset. FDA stresses that these drugs have not shown any benefit for prophylaxis (prevention) or for hospitalized patients. Supply and distribution of these medications are currently restricted, although the Biden administration is taking steps to ramp them up.

Additional Resources

Information regarding the status of each foreign patent office and the availability of extensions of time in each jurisdiction.

Tracking executive orders, legislation, and other government actions related to COVID-19 by state and major locality across the U.S.