First it was the Alpha, Beta, Gamma, then the much dangerous Delta, and now the Lambda, all variants of the SARS-CoV-2 virus.
What do we really know about them? The Alpha, the first variant from the original strain that started in China, is supposedly the more transmissible one at about 50 percent. That we know already. The Beta and Gamma variants, well, not so much.
But what captured the world’s attention was the emergence of the Delta variant, supposed to be highly transmissible compared to Alpha, and now the Lambda, where not much is known yet.
The Delta variant
Guido David, PhD and a fellow at the OCTA Research Group, was one of the speakers during the “Data Behind the Delta” webinar organized by PhilCare, PhilLife, Comm&Sense and Stitch Solutions.
He said the Delta variant was first detected in India and has now overtaken all the other variants in the United Kingdom. This may be partially because the country relaxed its restrictions because they had sufficient vaccination at that time, according to Dr. David.
However, he cited this finding as country specific and largely depended on the level of vaccination.
In the Philippines, cases involving the Delta variant are exponentially increasing, he said, even more in early August. “What we’re seeing right now based on samplings, the percentage of Delta variant cases has increased to about 30 percent in the entire country. Based on genome sequencing, it was previously around 26 percent. This is concerning because the percentage of the Delta variant has been increasing for the past weeks.”
However, he noted the limitations in the country’s bio-surveillance capabilities where only 100 samples can be sequenced daily, and with around 8,000 cases noted daily that would be only 1 to 2 percent. But with the imposition of the stricter lockdown and decrease in mobility, it may have already impacted on the increase in cases, and it is seen to slow down further, says Dr. David.
Also, with regards to the reproduction number, or the average number of transmissions, it indicates a similar surge just like what happened last March here in the National Capital Region (NCR). “But we shouldn’t allow the reproduction number to go even higher, which would mean an increase in cases and more hospitals becoming full and overwhelmed.”
Right now, Dr. David said the goal is to reduce the reproduction number to less than one. “The Alpha variant reproduction number is four, which means one person can already infect four people. But if 75 percent of the people are vaccinated, meaning three out of the four will be protected from the virus and this can bring the reproduction number down to just one, which is the goal of pandemic management.”
However, it’s a different case with the Delta variant, which has a reproduction number of about five to eight, but Dr. David puts it at an average of six so the variant can infect up to six people. However, he said what he’s demonstrating is the value of vaccination in achieving herd immunity and stopping the spread of the virus. “By vaccinating more people, coupled with strict compliance to health protocols like wearing of face masks, the more will be protected and this will help stop, or even just limit, the spread of the virus.”
The Lambda (C.37) variant
We’re not even done yet with Delta and now here comes the Lambda variant, which started in Peru and reportedly is also highly transmissible. Not much is known yet regarding its infection rate or virulence, nor any clear evidence that current vaccines are ineffective against this strain.
According to Prof. Cynthia Saloma, Ph.D., of the University of the Philippines-Philippine Genome Center (UP-PGC), during the latest episode of University of the Philippines’ Stop Covid Deaths, cited data from the GISAID, or the Global Initiative on Sharing All Influenza Data, a public database for the sharing of information on genome sequencing of SARS-CoV-2.
She said that in April 2021, a lot of submitted data to the GISAID was Alpha, but in a short period this was overtaken by Delta with supposedly 99 percent of submission was more for Delta.
And now there’s the Lambda variant, which Dr. Saloma said has already spread to 34 countries (mostly in South America) including the Philippines.
She said about 4,150 cases with the Lambda variant were already sequenced with the earliest case noted in Peru in December 2020.
She said the United States Centers for Disease Control and Preventtion (US-CDC) does not see the Lambda as a variant of interest (VOI) because it does not seem to be spreading too much compared to Delta since its spread is happening mostly in South America. However, the World Health Organization (WHO) thinks otherwise.
In the Philippines, there’s only one Lambda case detected out of more than 11,000 genome sequences, coming from a 35-year-old female. However, Dr. Saloma noted that in vitro data in Japan showed that mutation in the Lambda variant has the potential for immune evasion.
She stated that a lot more data as to the clinical and epidemiologic implication of this variant is needed and reiterated that vaccines will still work against preventing severe cases and hospitalization.
Again, health experts are one in saying that the more people are vaccinated, the less the viruses will mutate and more people will be protected.