Since You Asked – There’s a lot of conflicting information online about the Delta Variant; what’s true?


The Delta variant first emerged in India in April and has quickly become the dominant strain of COVID-19 throughout the world. There is no evidence that suggests the Delta variant is more dangerous than other variants, however, we know that it is more contagious. Dr. Mike Ryan, executive director of the WHO’s health emergencies program, says the Delta variant has the potential “to be more lethal because it’s more efficient in the way it transmits between humans and it will eventually find those vulnerable individuals who will become severely ill, have to be hospitalized and potentially die.” Viruses constantly mutate and generally mutations are not dangerous. However, the Delta variant mutation happens to be dangerous because it has mutated so that it can easily latch onto the cells in our bodies - making it more contagious than other variants. People are therefore growing concerned about the COVID-19 vaccine’s efficacy in protecting against Delta and other variants. Concern is also growing around the loosening mask restrictions.

So, What About Vaccine Efficacy?

Given these new developments, countries around the world are beginning to turn their attention towards studying vaccine efficacy against the Delta variant. On Friday, July 2nd, the Wall Street Journal reported that 90% of new COVID cases in Israel were linked to the Delta variant and nearly half of the infected population were inoculated. New data from the Israeli government suggests that the Pfizer vaccine is only 64% effective against the Delta variant, but 93% effective in preventing severe illness and 97% effective in preventing hospitalizations. It should be noted however that this data is preliminary, from one country only, and should not be used to draw general conclusions.

In fact, health researchers suggest it is still too early to make any set determinations regarding how much the Delta variant affects vaccine efficacy. Dr. Ashish Jha, Dean of Brown University's School of Public Health, tweeted, “Best data still suggest mRNA vaccines offer high degree of protection against infection and superb protection against severe illness. Lets await more data but as of now ... If you're vaccinated, I wouldn't worry.” 

The Verdict

Are vaccinated people at risk for contracting the virus?
Yes, it is possible. But vaccinated people will most likely experience mild or no symptoms if infected. 

Moderna and Johnson & Johnson both state that their COVID-19 vaccines are effective against several variants including the Delta variant, but efficacy rates have not been made public. 

The Latest Information on how to Slow the Spread

The World Health Organization recently updated its mask guidelines, advising fully vaccinated people to wear masks as the Delta variant continues to spread. Explaining their rationale behind this decision, Dr. Mariangela Simao, WHO assistant director-general for access to medicines and health products, said, “Vaccine alone won’t stop community transmission. People need to continue to use masks consistently, be in ventilated spaces, hand hygiene ... the physical distance, avoid crowding. This still continues to be extremely important, even if you’re vaccinated when you have a community transmission ongoing.” Community transmission is when people have been exposed to a virus in an area but do not know how or where they were infected. 

In contrast, The Centers for Disease and Control, CDC maintain that fully vaccinated people do not need to wear masks outdoors, but masks are still required on planes, trains, and other forms of public transportation. Addressing the  differences in guidelines, Dr. Ashish Jha said, “The W.H.O. is looking at a world that is largely unvaccinated, so this makes sense. If I were living in Missouri or Wyoming or Mississippi, places with low vaccination rates, I would not be excited about going indoors without wearing a mask — even though I’m vaccinated.” 

The National Women’s Health Network Recommendations

Based on our analysis of all currently available information, we recommend that if you are vaccinated and part of a high risk population or live in a place with low vaccination rates, wear a mask to protect yourself against the Delta variant. If you live in highly vaccinated areas but feel uncomfortable forgoing a mask during the Delta outbreak, continuing to wear a mask will provide additional protection. Ultimately, as more data becomes available on the Delta variant and vaccine efficacy rates are disclosed, guidelines will be updated. 

Stay informed as guidelines and recommendations change:  COVID-19 Resource Page 


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