COVID-19 Variant Gets Dominant Strain, Concerns Growing on Older People’s Fewer Antibodies

Source: Google

Over the coming months, the highly contagious Delta variant of COVID-19, according to World Health Organisation (WHO), is expected to become the dominant strain of the virus.

Delta, which was first detected in India, has now been recorded in 124 territories, 13 more than last week, and already accounts for more than three-quarters of sequenced specimens in many major countries, the WHO said.

In its weekly epidemiological update, the United Nations health agency says, “it is expected that it will rapidly out-compete other variants and become the dominant circulating lineage over the coming months.”

Of the three other coronavirus variants of concern (VOCs), Alpha, first detected in Britain, has been reported in 180 territories (up six from last week), Beta, first detected in South Africa, in 130 (up seven) and Gamma, first detected in Brazil, in 78 (up three).

According to SARS-CoV-2 sequences submitted to the GISAID global science initiative over the four weeks to July 20, the prevalence of Delta exceeded 75 percent in several countries.

Those included Australia, Bangladesh, Botswana, Britain, China, Denmark, India, Indonesia, Israel, Portugal, Russia, Singapore and South Africa.

“Growing evidence supports the increased transmissibility of the Delta variant as compared to non-VOCs. However, the exact mechanism for the increase in transmissibility remains unclear,” said the WHO.

The Geneva-based organisation said overall, 3.4 million new COVID-19 cases were reported in the week to July 18—up 12 percent on the week before.

“At this rate, it is expected that the cumulative number of cases reported globally could exceed 200 million in the next three weeks”, WHO said.

The organisation said the global increases in transmission appeared to be driven by four factors: more transmissible variants; the relaxation of public health measures; increased social mixing and large numbers of unvaccinated people.

Cases were up 30 percent in the WHO’s Western Pacific region and up 21 percent in its European region.

The highest numbers of new cases were reported from Indonesia (350,273 new cases; up 44 percent),

Britain (296,447 new cases; up 41 percent), and Brazil (287,610 new cases; down 14 percent).

The number of weekly deaths, however, remained steady at 57,000, similar to the previous week and following a steady decline for more than two months.

In the meantime, older people appear to have fewer antibodies against the novel coronavirus, going by a new laboratory study from Oregon Health & Science University.

Antibodies are blood proteins that are made by the immune system to protect against infection. They are known to be key players in protection against SARS-CoV-2 infection.

The study is published in the Journal of the American Medical Association.

Senior author and Assistant Professor of molecular microbiology and immunology in the OHSU School of Medicine, Fikadu Tafesse, says “our older populations are potentially more susceptible to the variants even if they are vaccinated.”

Tafesse and colleagues emphasized that even though they measured diminished antibody response in older people, the vaccine still appeared to be effective enough to prevent infection and severe illness in most people of all ages.

“The good news is that our vaccines are really strong”, Tafesse said.

However, with vaccine uptake slowing in Oregon and across United States, researchers say their findings underscore the importance of promoting vaccinations in local communities.

Vaccinations reduce the spread of the virus and new and potentially more transmissible variants, especially for older people who appear to be more susceptible to breakthrough infections.

“The more people get vaccinated, the less the virus circulates”, Tafesse said. “Older people aren’t entirely safe just because they’re vaccinated; the people around them really need to be vaccinated as well. At the end of the day, this study really means that everybody needs to be vaccinated to protect the community.”

Researchers measured the immune response in the blood of 50 people two weeks after their second dose of the Pfizer vaccine against COVID-19. They grouped participants into age groups and then exposed their blood serum in test tubes to the original “wild-type” SARS-CoV-2 virus and the P.1 variant (also known as gamma) that originated in Brazil.

The youngest group—all in their 20s—had a nearly seven-fold increase in antibody response compared with the oldest group of people between 70 and 82 years of age. In fact, the laboratory results reflected a clear linear progression from youngest to oldest: The younger a participant, the more robust the antibody response.

“Older people might be more susceptible to variants than younger individuals,” Tafesse said.

The findings highlight the importance of vaccinating older people as well as others who may

be more vulnerable to COVID-19, said co-author Marcel Curlin, associate professor of medicine (infectious diseases) in the OHSU School of Medicine.

“The vaccine still produces strong immune responses compared with natural infection in most older individuals, even if they are lower than their younger counterparts”, Curlin said. “Vaccination in this group may make the difference between serious and mild disease, and likely reduces the chances of transmitting SARS-CoV-2 to another person.”

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