Lambda variant: How big of a threat does this COVID-19 strain pose?

Even as the Philippines is still dealing with the rising number of COVID-19 Delta cases, yet another new strain has been detected on Sunday, Aug. 15: the Lambda variant, which was first detected in Peru.

This strain is feared to be more transmissible than the Delta variant and is said to even affect vaccine efficacy. However, further studies need to be carried out and conducted to learn more about the Lambda strain. Currently, there are no published studies on the variant, just preprints, or preliminary studies still subject for the review and scrutiny of other scientists.

How transmissible is the Lambda variant?

The Lambda variant, also known as the C.37, has now been detected in 30 countries and has been spreading rapidly in South America, where it is now the most dominant strain in Peru (97% of cases in the country are of this variant), Argentina, Chile, and Columbia.

With the first detected Lambda case in the Philippines raising public concern, infectious disease expert Dr. Edsel Salvana wrote in a Facebook post that the Delta variant is still a bigger threat.

"I've been tracking VOCs (Variant of Concern) and VOIs (Variant of Interest) since the start of the pandemic, and for me, the scariest variant is still Delta," he said. "Lambda is a VOI. That means it has some scary mutations and may be more vaccine-resistant."

So far, early studies suggest that the Lambda strain is more infectious due to its "unusual combinations" of mutations. There are seven mutations on the spike protein—the outer shell of the virus—that make it easier for the virus to latch onto our cells and harder for our antibodies to neutralize it.

Because of these genetic markers, the World Health Organization (WHO) labeled Lambda as a variant of interest.

"The difference between a VOI and a VOC is that a VOC is proven to be more transmissible and/or vaccine-resistant, while a VOI can go either way," Salvana continued.

As of June 23, WHO designated the Lambda strain as a "variant under investigation."

“Lambda has been associated with substantive rates of community transmission in multiple countries, with rising prevalence over time concurrent with increased COVID-19 incidence," WHO said.

Do vaccines work against this strain?

Early lab data shows that the Lambda variant has an increased resistance to vaccines, which was also said about the Delta and Beta variants. Chilean researchers tested the Chinese-made Sinovac (Coronavac) vaccine's efficacy against the Lambda variant, which resulted in the vaccine working less effectively on the strain.

"The issue of Coronavac/Sinovac having decreased effect on Lambda is from a PREPRINT (not yet peer-reviewed), and is a LABORATORY STUDY using pseudotyped viruses with neutralizing antibodies," Dr. Salvana pointed out.

He added that real-world data from Chile—a country with prevalent Lambda cases—shows that Snovac prevents severe disease and death very well. "Preliminary data from Peru on Sinopharm where almost 80% is Lambda shows a 94% decrease risk of death."

Meanwhile, a study on mRNA vaccines (Pfizer and Moderna) showed that they were also effective against the Lambda variant.

"ALL vaccines work to prevent severe disease and death against ALL the variants. Get vaccinated now and drop your risk of severe disease and dying by 90%," Dr. Salvana wrote.

Meanwhile, former special adviser for the National TaskForce Against COVID-19 Dr. Tony Leachon said "We need ruthless consistency to adhere to the health protocol. It's very important to follow health standards right now."

Like Salvana, Leachon encouraged people to get vaccinated, "Each family member should encourage everyone to get vaccinated."