Delta Variant Detected in Provincetown COVID-19 Cluster

BOSTON — The Massachusetts Department of Public Health (DPH) announced on Friday that genetic sequencing of initial samples associated with the recent COVID-19 cluster in Provincetown tested positive for the Delta variant. While DPH has identified cases in the cluster associated with vaccinated individuals, the total number of cases among vaccinated people in Massachusetts remains extremely low, at 0.1%, or 5,166 cases, out of more than 4.3 million fully vaccinated residents.

Both the State Public Health Laboratory and the Broad Institute of MIT and Harvard have contributed to sequencing efforts in Massachusetts during the pandemic. This sequencing data contributes to the tracking of clusters and patterns of disease spread. Both labs identified the Delta variant in cases associated with this cluster, and additional specimens from the Provincetown cluster are continuing to be prioritized for sequencing. No new variants have been identified. Massachusetts has in-state laboratory capacity to sequence variants and does not have to rely on out-of-state laboratories.

The Delta variant is known to be more transmissible than the original COVID-19 virus. Individuals infected with the Delta variant tend to have more virus in their respiratory tract than other variants, and infected individuals may carry the virus longer. These two factors contribute to the increased transmissibility seen with the Delta variant.

Since its original identification in the U.S., the Delta variant has spread rapidly, and the Centers for Disease Control and Prevention recently estimated that 83% of cases during the July 4-17 period are attributable to this variant nationally. The estimates during that same time period for Region 1 (which includes the six New England states) suggest Delta accounts for 68% of cases during the same time period.