the number of reported COVID-19 vaccine breakthrough cases is likely a substantial undercount of all SARS-CoV-2 infections among fully vaccinated


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While the news of falling covid cases in the US may appear positive on the surface, large majority of new infections, reinfections and post vaccination breakthrough infections cases remain unreported. Mild and asymptomatic cases contribute to Sarscov2 spread and are of public health significance. As of May 30, the US covid fatalities are standing at the similar to May-summer 2020 numbers 3500-5000 per week despite half of the US population being vaccinated proving low to negligible vaccine impact. Significant 3-4 weeks reporting delays , decrease in testing contribute to lower case statistics along with seasonally lower severe disease incidence and public fatigue.

ICYMI, beginning May 1, 2021, CDC transitioned from monitoring all reported COVID-19 vaccine breakthrough infections to investigating only those among patients who are hospitalized or die. Per CDC, the number of reported COVID-19 vaccine breakthrough cases is likely a substantial undercount of all SARS-CoV-2 infections among fully vaccinated. The national surveillance system relies on passive and voluntary reporting, and data might not be complete or representative. Many with vaccine breakthrough infections, especially those who are asymptomatic or who experience mild illness, might not seek testing or treatment while remaining a source of more infection spread. Unfortunately, very small amount ~2% of all SARS-CoV-2 data is sequenced to continue tracking new more transmissible and virulent variants spread as cases and fatalities are expected to rise this fall and winter.

A total of 10,262 SARS-CoV-2 vaccine breakthrough infections had been reported from 46 U.S. states and territories as of April 30, 2021. Among these cases, 6,446 (63%) occurred in females, and the median patient age was 58 years (interquartile range = 40–74 years). Based on preliminary data, 2,725 (27%) vaccine breakthrough infections were asymptomatic, 995 (10%) patients were known to be hospitalized, and 160 (2%) patients died. Among the 995 hospitalized patients, 289 (29%) were asymptomatic or hospitalized for a reason unrelated to COVID-19. The median age of patients who died was 82 years (interquartile range = 71–89 years); 28 (18%) decedents were asymptomatic or died from a cause unrelated to COVID-19. Sequence data were available from 555 (5%) reported cases, 356 (64%) of which were identified as SARS-CoV-2 variants of concern,§ including B.1.1.7 (199; 56%), B.1.429 (88; 25%), B.1.427 (28; 8%), P.1 (28; 8%), and B.1.351 (13; 4%).

Important to note politically motivated reopening is coming when themost concerning variants such as Indian B1617.2 is already found in the US, new variant detected in Vietnam and even B1351 escape vaccine immunity or neutralising antibodies protection is significantly reduced. , thereby focusing on the cases of highest clinical and public health significance.