With input from Dr Monica Vasudev

1570: Post-vaccine COVID

• In a report published in the CDCs Morbidity and Mortality Weekly Report,  22 "breakthrough" infections diagnosed in around 15,000 Chicago-area nursing home residents and staff were seen two weeks or more after a second mRNA COVID-19 vaccine dose
• At a Kentucky nursing home, 22 of 127 residents and staff developed infectionat least two weeks after the second mRNA vaccine dose. Virus sequencing showed an unusual variant, noted a separate MMWR report
• Two breakthrough infections were noted among 417 employees and students at Rockefeller University in New York City receiving two mRNA vaccine doses, which were notable for the particular virus strains, reported the New England Journal of Medicine

They appear to be more common among older individuals, and the vaccines do not offer complete protection against serious illness or death.

Chicago-Area

Investigation from February to March 31

627 confirmed infections were identified in 75 nursing homes

1. 447 of these were in residents and staff not vaccinated at all
2. 145 were in individuals who had received one dose
3. 13 were in individuals who hadnt completed two weeks from their second vaccine dose.

Among the 22 individuals with definite breakthrough infections, 12 were in residents and 10 in staff. Fourteen cases were asymptomatic, four needed hospital admission, and one was fatal.  The resident who died was also reported to have a bacterial bloodstream infection and a urinary tract infection, along with chronic conditions known to increase the risk for severe COVID-19.

Kentucky Nursing Home

Vaccination program was completed on February 21.

About 90% of the nursing home’s 83 residents and a little more than half of the 116 staff members had received two doses of the Pfizer/BioNTech vaccine.

On March 1, the first case which led to an outbreak was detected in an unvaccinated staff member through antigen testing. Over the next few weeks, 18 residents and four more staff members were found to be infected, all over two weeks after their last vaccine dose.

Twelve cases among residents were asymptomatic; two needed hospitalization, and one resident died. Two staff members who had breakthrough infections developed symptoms that did not require hospitalization.

Virus sequencing from 27 cases at the facility revealed an unusual strain known as R.1.

It included mutations such as E484K.

Rockefeller University

Starting January 21, when two weeks had passed since the first vaccinees had received their second doses of either the Pfizer/BioNTech or Moderna vaccines, investigators started looking for breakthrough cases, with 417 individuals considered eligible.

By March 17, two cases were found - both in previously healthy women; one age 51 and the other 65, who developed mild symptomatic illness 19 and 36 days, respectively, following the second doses.

Viral RNA sequencing showed that both of them were infected with variants differing from each other and also from the original Wuhan strain. In Patient 1, the virus included the E484K mutation and D614G mutation, while virus from Patient 2 had D614G and S477N mutation. Both were distinct from variants such as B.1.1.7 and B.1.526 known to be dominant in New York City.

[Medpage Today]

Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA