Connect with us

Medical Science

Dramatic decline in effectiveness of all three COVID-19 vaccines over time in U.S: Study

Published

on

(Asian News Hub) – As the Delta variant of SARS-CoV-2 became the dominant strain of the virus in the US, all three COVID-19 vaccines available to Americans lost much of their protective power, with vaccine efficacy among nearly 800,000 veterans dramatically dropping between 35% and 85% in just six months, according to a new study published Thursday (Nov. 4) in the journal Science.

By September, Moderna’s two-dose COVID-19 vaccine was only 58% effective.

The effectiveness of Pfizer’s two-dose vaccine fell to 45%.

And most strikingly, the protective power of Johnson & Johnson’s single-dose vaccine plunged to just 13%.

Medical Science

What is Omicron and what makes it a variant of concern (VoC)?

Published

on

(Asian News Hub) – It is a new variant of SARS-CoV-2 that has recently been reported from South Africa on 24th November 2021 called as B.1.1.529 or Omicron (based on Greek alphabets like alpha, beta, delta etc). This variant has shown a very large number of mutations, especially more than 30 on the viral spike protein, which is the key target of the immune response.

Given the collection of mutations in Omicron, which earlier individually have been associated with increased infectivity and/or immune evasion, and the sudden rise in number of positive cases in South Africa, World Health Organization has declared Omicron as a Variant of Concern (VoC).

Can the currently used diagnostics methods, detect Omicron?

The most accepted and commonly used method of diagnostic for SARS-CoV- 2 Variant is RT-PCR method. This method detects specific genes in the virus, such as Spike (S), Enveloped (E) and Nucleocapsid (N) etc to confirm the presence of virus. However, in case of Omicron, as the S gene is heavily mutated, some of the primers may lead to results indicating absence of the S gene (called as S gene drop out). This particular S gene drop out along with the detection of other viral genes could be used a diagnostic feature of Omicron. However, for final confirmation of the omicron variant genomic sequencing is required.

How concerned should we be about the new VoC?

WHO declares a variant as a VoC after assessment when there is increase in transmissibility or detrimental change in COVID-19 epidemiology; OR increase in virulence or change in clinical disease presentation; OR decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics. (Source: WHO)

Also Read: Polluted air coming from Pakistan; UP govt tells SC

It is important to highlight that Omicron has been declared VoC based on the observed mutations, their predicted features of increased transmission and immune evasion, and preliminary evidence of detrimental change in COVID-19 epidemiology, such as increased reinfections. The definitive evidence for increased remission and immune evasion is awaited.

What precautions should we take?

The precautions and steps to be taken remain same as before. It is essential to mask yourself properly, take both doses of vaccines (if not yet vaccinated), maintain social distancing and maintain good ventilation to the maximum possible.

Will there be a third wave?

Omicron cases are increasingly being reported from countries outside of South Africa and given its characteristics, it is likely to spread to more countries including India. However, the scale and magnitude of rise in cases and most importantly the severity of disease that will be caused is still not clear. Further, given the fast pace of vaccination in India and high exposure to delta variant as evidenced by high seropositivity, the severity of the disease is anticipated to be low. However, scientific evidence is still evolving.

Will the existing vaccines work against Omicron?

While, there is no evidence to suggest that existing vaccines do not work on Omicron, some of the mutations reported on Spike gene may decrease the efficacy of existing vaccines. However, vaccine protection is also by antibodies as well as by cellular immunity, which is expected to be relatively better preserved. Hence vaccines are expected to still offer protection against severe disease and, vaccination with the available vaccines is crucial. If eligible, but not vaccinated, one should get vaccinated.

Why do variants occur?

Variants are normal part of evolution and as long as the virus is able to infect, replicate and transmit, they will continue to evolve. Further, not all variants are dangerous and most often than not, we don’t notice them. Only when they are more infectious, or can reinfect people etc they gain prominence. The most important step to avoid generation of variants is to reduce the number of infections.

Continue Reading

Medical Science

Moderna chief predicts existing COVID-19 vaccines will struggle with Omicron variant

Published

on

(Asian News Hub) – The chief executive of Moderna has just predicted that existing COVID-19 vaccines will be much less effective at tackling Omicron than earlier variants of SARS-CoV-2 and warned it would take months before pharmaceutical companies can manufacture new variant-specific jabs at scale, FR reported.

Stéphane Bancel said the high number of Omicron mutations on the spike protein, which the virus uses to infect human cells, and the suspected potential rapid spread of the variant in South Africa, suggested the current crop of COVID-19 vaccines may need to be modified next year to beat Omicron.

Also Read: Plastic Factory gutted in midnight blaze at SIDCO Pulwama

“There is no world, I think, where [the effectiveness] is the same level, we had with Delta,” Bancel said.

He added: “I think it’s going to be a material drop. I just don’t know how much because we need to wait for the data. But all the scientists I’ve talked to . . . are like ‘this is not going to be good’.”

Continue Reading

Medical Science

Omicron has 30+ mutations in spike protein region, may bypass vaccines: Dr Guelria AIIMS chief

Published

on

Says efficacy of vaccines, including those in use in India, needs to be evaluated ‘critically’

(Asian News Hub) – The new Omicron variant of coronavirus has reportedly got over 30 mutations in the spike protein region giving it the potential to develop a immunoescape mechanism, and thus the efficacy of vaccines against it needs to be evaluated critically, PTI reported as saying by AIIMS chief Dr Randeep Guelria.

The presence of spike protein facilitates a virus’ entry into the host cell and is responsible for making it transmissible and causing infection.

Also Read: As new Covid variant surfaces, Doctors body calls for enhanced genome sequencing

“The new variant of coronavirus reportedly has got more than 30 mutations in the spike protein region and therefore has the potential of developing immunoescape mechanisms. As most vaccines (work by) forming antibodies against the spike protein, so many mutations at the spike protein region may lead to a decreased efficacy of COVID-19 vaccines,” AIIMS Director Dr Randeep Guelria told PTI.

In such a scenario, the efficacy of vaccines, including those in use in India, needs to be evaluated “critically”, he said.

The future course of action will depend on what more data on its transmissibility, virulence and immunoescpae shows, he said.

Also Read: 14-yr-old boy from Mirgund dies at JVC Bemina, family alleges medical negligence

The Indian SARS-CoV-2 Genomic Consortia INSACOG is closely tracking the new variant of COVID-19 called B.1.1.529 and its presence has not been detected yet in the country, officials have said.

Dr Guleria emphasised the need to be very vigilant and having aggressive surveillance both for international travellers and in the region where there is a sudden increase in the number of cases.

“Also, we must ask everyone to religiously follow Coivd-appropriate behaviour and not let their guards down. Also, it has to be ensured that people get both the doses of vaccine and those who have not yet taken the jab are encouraged to come forward to take it,” he said.

The new, and potentially more contagious variant, was first reported to the World Health Organization (WHO) from South Africa on November 24. It has since been identified in Botswana, Belgium, Hong Kong and Israel among other countries.

On Friday, it was designated a ‘Variant of Concern’ by the WHO, which named it Omicron. A ‘Variant of Concern’ is the WHO’s top category of worrying Covid-19 strain.

The Centre on Thursday asked all states and union territories to conduct rigorous screening and testing of all international travellers coming from or transiting through South Africa, Hong Kong and Botswana.

In a letter to the additional chief secretary/principal secretary/secretary (Health) of all states and union territories, Union Health Secretary Rajesh Bhushan asked them to ensure that samples of travellers turning positive are sent to the designated genome sequencing laboratories promptly.

Continue Reading

Trending