COVID-19 Roundup: Booster Doses, COVID-19 Testing, Post-Infection Management, Potential Drug Interactions

Expanded COVID-19 Vaccine Booster1

Children aged 5 to 11 years are now eligible for a booster dose of the Pfizer-BioNTech COVID-19 following an amendment to the emergency use authorization by the US Food and Drug Administration (FDA).

This patient population is now eligible for a single booster dose at least 5 months following the completion of the primary vaccine series.

This approval follows the results of an analysis on the immune response data of the randomized, controlled trial that was utilized to provide approval for the primary dose series of the Pfizer-BioNTech vaccine in this patient population in October 2021.

Common adverse effects include pain, redness and swelling at the injection site, fatigue, headache, muscle or joint pain, chills and fever.

First Non-Prescription COVID-19, Respiratory Infection Test2

The FDA has approved the first non-prescription multi-analyte test to detect both common respiratory viral infections as well as COVID-19.

The test, the Labcorp Seasonal Respiratory Virus RT-PCR DTC test, is able to identify and differentiate between influenza A, influenza B, respiratory syncytial virus (RSV), and SARS-CoV-2.

Individuals self-collect a nasal swab sample with the home sample collection kit before sending the sample out for laboratory testing. Results are then posted to the online portal. Individuals aged 14 years and older may self-collect samples under adult supervision, and individuals 2 years or older may collect samples with adult assistance.

Readmission After Hospitalization3

One in 9 individuals who were hospitalized with COVID-19 died or were readmitted within 30 days of discharge, according to the results of a retrospective cohort study.

Included in the study were 46,412 individuals who were admitted to the hospital within 14 days of their positive COVID-19 test result between January 2020 and September 2021 in Alberta and Ontario, Canada. Of the 34,846 total individuals that were discharged alive, 10.5% (n=3173) of the 30,336 patients that were hospitalized for 30 days or less were readmitted. In comparison, 12.8% (n=579) of the 4510 individuals who were hospitalized for more than 30 days died or were readmitted.

Although some expected high rates of readmission after COVID-19 hospitalizations, study authors found that outcomes in the 30 days after discharge were consistent with admissions for other medical diagnoses.

“Thus, current system approaches to transitioning patients from hospital to home do not appear to need adjustment. However, future research should determine other system effects for COVID-19 survivors, particularly with respect to postacute COVID-19 symptomatology,” they noted.

Thrombosis, Death and COVID-194

Approximately 1% of individuals developed venous or arterial thrombosis within 90 days following COVID-19 infection, according to the results of a European cohort study.

Researchers utilized primary care records from the Netherlands, Italy, Spain, and United Kingdom, as well as outpatient specialist records from Germany and a Spanish database on hospital admissions to examine the risk of thrombosis and death in patients after recovery from COVID-19.

The results indicated that the cumulative 90-day incidence for venous thromboembolism ranged from 0.2% to 0.8% among individuals with COVID-19, and up to 4.5% for individuals with COVID-19 that required hospitalization. For arterial thromboembolism, the cumulative 90-day incidence was 0.1% to 0.8%, and 3.1%, respectively. The incidence of death was 1.1% to 2.0%, and 14.6%, respectively.

Drug Interactions with Nirmatrelvir/Ritonavir5

The Infectious Diseases Society of America’s guideline panel on COVID-19 treatment and management has released a new guide on managing drug interactions with nirmatrelvir/ritonavir (Paxlovid).

Nirmatrelvir/ritonavir is to be initiated for the authorized patient population within 5 days of symptom onset. This population includes individuals aged 12 years or older who weigh at least 40 kg with mild to moderate disease who are at risk of progression to severe disease.

Rivaroxaban and salmeterol should not be used with nirmatrelvir/ritonavir due to severe interactions. Commonly prescribed medications that may interact with nirmatrelvir/ritonavir include hormonal contraceptives with ethinyl estradiol, most statins, and oral, inhaled and nasal steroids, among others. Health care practitioners should monitor patients and check for all medication interactions before and during treatment with nirmatrelvir/ritonavir.


—Leigh Precopio



  1. Coronavirus (COVID-19) Update: FDA expands eligibility for Pfizer-BioNTech COVID-19 vaccine booster dose to children 5 through 11 years. News release. US Food and Drug Administration; May 17, 2022. Accessed May 17, 2022.
  2. Coronavirus (COVID-19) Update: FDA authorizes first COVID-19 test available without a prescription that also detects flu and RSV. News release. US Food and Drug Administration; May 16, 2022. Accessed May 17, 2022.
  3. McAlister FA, Dong Y, Chu A, et al. The risk of death or unplanned readmission after discharge from a COVID-19 hospitalization in Alberta and Ontario. CMAJ. 2022;194(19);666-673. doi:10.1503/cmaj.220272
  4. Burn E, Duarte-Salles T, Fernandez-Bertolin S, et al. Venous or arterial thrombosis and deaths among COVID-19 cases: a European network cohort study. Lancet Infect Dis. Published online May 13, 2022. doi:10.1016/S1473-3099(22)00223-7
  5. Management of drug interactions with nirmatrelvir/ritonavir (paxlovid): resource for clinicians. Infectious Diseases Society of America. May 6, 2022. Updated May 6, 2022. Accessed May 17, 2022.