Addressing concerns and confusion (7/2/21)

A Message from the COVID-19 Coordinator


  • What do we know about the Delta variant?
  • What about the WHO, the CDC, and masks?

Dear Members of the Yale Community,

In recognition of continuing low levels of COVID-19 infection in our area and rising rates of vaccination in our community, Provost Scott Strobel and Senior Vice President for Operations Jack Callahan announced earlier this week that fully vaccinated individuals who have submitted vaccination documentation to the university will not be required (with some exceptions) to mask, physically distance, or complete certain health checks or testing while on Yale’s campus, effective July 6. At the same time, concerns are circulating in the media about an increase in new cases of COVID-19 in some parts of the country and the world, attributable in part to the growing prominence of the Delta variant. Seeming differences in mask guidance from the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) have also generated some confusion.

So what does this mean for our community?

What do we know about the Delta variant?

Mutation in viruses is common, and we have already seen the emergence of several COVID-19 variants throughout the pandemic. Currently, the one causing the most concern is the Delta variant, which was first identified in India late last year, and which appears to be much more easily transmissible than both the original virus and other variants. Delta now accounts for more than 25% of new cases of COVID-19 in the United States, and the CDC has identified it as a “variant of concern.”

The good news is that the vaccines currently available in the United States appear to provide strong protection for those who have been fully vaccinated. However, the variant may cause localized outbreaks in areas where fewer people are vaccinated. Indeed, vaccination is the most effective measure not only to reduce the spread of the Delta variant but also to prevent new variants from emerging. In the words of Dr. Anthony Fauci, “viruses cannot mutate if they don’t replicate [by infecting people].”

What about the WHO, the CDC, and masks?

This week, the WHO issued guidance recommending that fully vaccinated individuals continue to take precautions when in public spaces, including wearing a mask and practicing physical distancing. However, the CDC has not changed its guidance, which allows those who are fully vaccinated to go without masks in most situations. What should we make of this seeming discrepancy?

  • The WHO guidance is based on global infection and vaccination rates, taking into consideration the many areas of the world where vaccination rates are low, vaccine efficacy is variable, and rates of COVID-19 transmission remain high.
  • Both the WHO and the CDC recognize that local decisions about protective measures can and should be based on local conditions. In areas in which there are low levels of transmission and high levels of vaccination, communities may consider modifying these preventative measures for those who are fully vaccinated. Connecticut—indeed, much of the Northeastern United States—falls into this category. Recent changes in our university health and safety measures reflect these favorable conditions and are aligned with current guidance from both the WHO and the CDC.

Yale’s Public Health Committee is closely tracking and advising university leaders on the state of the pandemic, the impact of variants, and current guidance from national and international public health experts. The university will continue to adjust its health and safety measures in response to changes in conditions and in accordance with guidance from the Committee. As I explained in my message of last week, one important action you can take is to stay informed about the state of the pandemic in your own community and in the communities to which you might travel and to modify your health and safety measures accordingly.

I hope this information has addressed some of your questions and concerns. As the holiday weekend approaches, I wish you safe and enjoyable times with family and friends.

Stephanie S. Spangler, M.D.
Vice Provost for Health Affairs and Academic Integrity
Clinical Professor of Obstetrics, Gynecology and Reproductive Sciences
University COVID-19 Coordinator