The Homeland Security Digital Library (HSDL) maintains a collection of the Centers for Disease Control’s (CDC) Morbidity and Mortality Weekly Report (MMWR), which collects and analyzes data from the United States Department of Health and Human Services (HHS) on epidemiology and public health. Each issue of the MMWR is packed with raw and analyzed public health data and scientific studies from some of the top minds in the United States. In light of the COVID-19 (coronavirus disease 2019) epidemic, we are highlighting some of the most current and informative COVID-related studies included in their weekly reports. 

Here are some important articles you may have missed from Volume 71, Issues 11-15 of the Centers for Disease Control’s Morbidity and Mortality Weekly Report (MMWR) Series. 

April 15, 2022 / No. 15 Featured Article: 

“Effectiveness of COVID-19 mRNA Vaccination in Preventing COVID-19–Associated Hospitalization Among Adults with Previous SARS-CoV-2 Infection — United States, June 2021–February 2022”

This study was done to assess effectiveness of COVID-19 mRNA vaccinations in adults who had previously been infected with the virus and then later become re-infected.  The study determined that “vaccine effectiveness against reinfection leading to hospitalization during the Omicron-predominant period was approximately 35% after dose 2, and 68% after a booster dose.”

April 8, 2022 / No. 14 Featured Articles: 

“Cardiac Complications After SARS-CoV-2 Infection and mRNA COVID-19 Vaccination — PCORnet, United States, January 2021–January 2022”

It has been discussed that COVID-19 Vaccinations have a risk factor for cardiac issues; however, this study was done to compare cardiac complications in individuals after vaccination versus those who developed cardiac complications from SARS-CoV-2 Infection.  The study concludes that “the risk for cardiac complications was significantly higher after SARS-CoV-2 infection than after mRNA COVID-19 vaccination for both males and females in all age groups.”

“Notes from the Field: SARS-CoV-2 Omicron Variant Infection in 10 Persons Within 90 Days of Previous SARS-CoV-2 Delta Variant Infection — Four States, October 2021–January 2022″

This study “highlights potential limits of infection-induced immunity against novel variants,” while reviewing re-infection in individuals within 90 days of previous infection.  It is noted that there is some difficulty in evaluation for the generalized public due to possible “prolonged shedding from earlier infection” and not true re-infection.  The small number of people evaluated in this note were individuals decidedly known to have been first infected with the Delta Variant, and then re-infected with Omicron within 90 days.

April 1, 2022 / No. 13 Featured Article: 

“Effectiveness of Homologous and Heterologous COVID-19 Booster Doses Following 1 Ad.26.COV2.S (Janssen [Johnson & Johnson]) Vaccine Dose Against COVID-19–Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Adults — VISION Network, 10 States, December 2021–March 2022”

This article studied the “vaccine effectiveness (VE) of different booster strategies, ” namely for persons who received solely the Janssen (Johnson & Johnson) vaccine (either 1 dose or 2), versus those who received the Janssen vaccine along with a booster of another vaccine type, and also versus three doses of a different mRNA vaccine.  The study revealed that “VE against COVID-19–associated emergency department/urgent care visits was 24% after 1 Jansen dose, 54% after 2 Jansen doses, and 79% after 1 Janssen/1 mRNA dose, compared to 83% after 3 mRNA doses.”

March 25, 2022 / No. 12 Featured Article: 

“Effectiveness of mRNA Vaccination in Preventing COVID-19–Associated Invasive Mechanical Ventilation and Death — United States, March 2021–January 2022”

This study determined that “Receiving 2 or 3 doses of an mRNA COVID-19 vaccine was associated with a 90% reduction in risk for COVID-19–associated IMV [Invasive Mechanical Ventilation] or death. Protection of 3 mRNA vaccine doses during the period of Omicron predominance was 94%.”

March 18, 2022 / No. 11 Featured Articles: 

“The Advisory Committee on Immunization Practices’ Recommendation for Use of Moderna COVID-19 Vaccine in Adults Aged ≥18 Years and Considerations for Extended Intervals for Administration of Primary Series Doses of mRNA COVID-19 Vaccines — United States, February 2022”

This article discusses the Advisory Committee on Immunization Practices recommendation to extend the timeframe for some people between the first and second doses of mRNA COVID-19 vaccination to 8 weeks instead of 3 weeks (Pfizer) or 4 weeks (Moderna).

“Hospitalization of Infants and Children Aged 0–4 Years with Laboratory-Confirmed COVID-19 — COVID-NET, 14 States, March 2020–February 2022”

During the Omicron predominance period, infants and children up to age 4 were five times more likely than during the Delta predominance to be hospitalized.  This article provides further information and strategy for preventative measures against COVID-19 infections in young children.

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For more information on COVID, visit our Coronavirus Disease (COVID-19) Resource Archive. You can also find pandemic-related resources in our HSDL In Focus on Pandemics and Epidemics, and public health statistical resources in our Research Tools. Please note that an HSDL login is required to view some of these resources. 

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