Vaccine-disrupted infections (VBT) occur in individuals even after being vaccinated against a particular pathogen. With the drastic increase in the number of cases of coronavirus disease (COVID-19) caused by the Delta variant of the coronavirus 2 severe acute respiratory syndrome (SARS-CoV-2) in the United States of America, understanding the rate and the clinical features associated with VTE among previously vaccinated individuals is of critical public health importance.
In a recent study published on the Preprint Server medRxiv *, researchers conducted a pilot study to assess the prevalence and characteristics of BVT through the use of sequencing and case data from Washoe County, Nevada, available from the Washoe County Health District (WCHD) and the Nevada State Public Health Laboratory (NSPHL).
To study: A review of groundbreaking SARS-CoV-2 vaccine infections and associated clinical outcomes. Image Credit: David Pereiras / Shutterstock.com
Analysis of WCHD public health data
In the current study, researchers collected all available public health data from February 12, 2021 to July 29, 2021. A total of 6,399 new cases of COVID-19 were reported during this period, of which 6,128 (95 , 8%) were successful. go back to their sources. Of these 6,399 cases, the health district identified 339 (5.5%) as breakthrough infections.
Cases of VBT were defined as any positive reverse transcriptase polymerase chain reaction (RT-PCR) test for individuals fully vaccinated for 14 days or more, prior to symptom onset or routine testing. WCHD collected individual-level VBT data for 338 cases out of the 339 plots.
Parameters recorded on these VBTs included demographic data such as age, sex, sex and race / ethnicity, as well as clinical data such as vaccine type and dosing regimen, onset of symptoms. symptoms ; hospitalization or death. Information on cycle cutoff (Ct) values and variants of interest, mainly from NSPHL and other partner laboratories as needed, was also collected.
VBT accounted for a small share of total infections between February 12 and July 29, 2021. The 338 reported cases of VBT represented only 0.14% among the vaccinated population of Washoe during the study period, compared to a rate 2.54% among the unvaccinated.
Serious outcomes in those vaccinated were also rare. Of the 5,961 cases found, 289 (86%) vaccinated individuals presented symptomatic infections, but only 17 were hospitalized (5%).
No deaths have been reported in cases of VBT, and hospitalizations have mainly been among the elderly. However, older people were less prone to breakthrough infections and more likely to present without symptoms compared to younger age groups.
Implications of the study
The current analysis from Washoe County, Nevada, showed a more than 18-fold lower rate of breakthrough infections in those vaccinated compared to the rate of infections in unvaccinated people. More importantly, the rates of severe illness were low among those vaccinated.
These results underscore the efficacy of vaccines in preventing serious infections and hospitalizations. There is already a growing body of data that can reassure the public about the true effectiveness of COVID-19 vaccines.
However, it should be noted that the data discussed here is part of a pilot dataset used to analyze vaccination results. Nonetheless, this analysis adds to the existing literature describing the risks of VBT and emphasizes the need for health authorities to monitor changing trends in vaccine discovery data.
medRxiv publishes preliminary scientific reports that are not peer reviewed and, therefore, should not be considered conclusive, guide clinical practice / health-related behavior, or treated as established information