The “delta variant”, the new COVID-19 variant that has its origin in India, has rattled the world as the fight to contain COVID-19 keeps getting complicated by emerging variants.

Before now, there had been other variants in the UK, Brazil, South Africa etc. As of April, the Alpha variant was the dominant variant in the US. Now there is “delta plus” a more deadly mutant of the delta variant, that India described as “variant of concern”.

The World Health Organization (WHO), said it’s the fastest and fittest coronavirus strain yet, and it will “pick off” the most vulnerable people.

“It 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,” Dr. Mike Ryan, executive director of the WHO’s health emergencies program, said during a news conference.

Delta plus has toppled the talk of the delta variant without minimizing its impact, augmenting the variant roller-coaster trajectory that has undermined the vaccination outcome to a great extent.

Alpha was the most dominant variant until delta showed up and took its place with 60% more severe effect.

Delta has now spread to 92 countries, Maria Van Kerkhove, the WHO’s technical lead for COVID, said. At a White House briefing on COVID-19 on Tuesday, Dr. Anthony Fauci of the National Institutes of Health said 20.6% of new cases in the U.S. are due to the Delta variant.

The Centers for Disease Control and Prevention, said it’s on its way to becoming the dominant variant in the nation.

The United Kingdom recently saw delta become the dominant strain there, surpassing alpha variant, which was first detected in the country last fall. The delta variant now makes up more than 60% of new cases in the U.K.

Israel, the first country to have the highest number of its population fully vaccinated, is now grappling with a new spike in COVID-19 cases. The country recorded 125 new cases on Monday, and the director of Israel’s health ministry, Dr. Nachman Ash said around 70% of new infections were the Delta variant.

The rate of the emergence of the variants, their spreading pace and how deadly they are, cast doubt on the chances of vaccination stopping COVID soon.

A growing number of vaccinated people are concerned about getting infected again by the variants as they appear to undermine vaccines’ efficacy.

A study of the delta variant in Scotland from the University of Edinburgh found that while the variant was associated with a doubling in the risk of hospitalization in those infected in the region, the Pfizer and AstraZeneca vaccines offered a 79% and 60% protection, respectively, against infection two weeks after the second dose. Another study from Public Health England showed that two doses of the Pfizer vaccine were 88% effective against symptomatic disease from the delta variant.

However, the Wall Street Journal reported Friday that about half of adults infected in the delta variant outbreak in Israel were fully vaccinated with the Pfizer-BioNTech vaccine, confirming the concern of many vaccinated people.

The WHO said last week that vaccinated people should continue to wear masks and observe other safety measures as the variants spread.

“People cannot feel safe just because they had the two doses. They still need to protect themselves,” Dr. Mariangela Simao, WHO assistant director-general for access to medicines and health products, said during a news briefing from the agency’s Geneva headquarters.

“Vaccine alone won’t stop community transmission,” Simao added. “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.”