Tag: PCR tests

Categories : COVIDTags :

Alcohol Curbs may Return while UK Red List may be Scrapped

On By ModernMedia
Image by Quicknews

With the COVID test positivity rate climbing above 30%, President Cyril Ramaphosa is widely expected to address the nation in the coming days. Health Minister Dr Joe Phaahla said on Friday that the National Coronavirus Command Council would be meeting on Tuesday or Wednesday to discuss new restrictions in the face of surging infections.

The main concern is centred around the large number of gatherings that will take place over the festive period: under Level 1 lockdown rules, gatherings of up to 750 individuals are permitted indoors. The Bureau for Economic Research issued a report saying that data so far indicates that there are fewer hospitalisations and less severe disease with the Omicron variant, in line with observations made since the start of the variant’s outbreak.

A partial ban on alcohol sales seems likely, according to a source cited by City Press: “He is considering proposing to the NCCC and cabinet a few adjustments, which include banning the sale of alcohol on weekends and public holidays until mid-January. Don’t be surprised when we have a family meeting before Thursday. He is serious about protecting the country.”

He initially had no plans to address the nation, sources said, but was motivated to change his view in light of the increasing rate of transmission.

Meanwhile, the UK appears set to scrap its controversial red list, which had been widely viewed as unfairly targeting South Africa. The red list amounted to a virtual travel ban, with travellers forced to pay £2285 (R48 400) per person for a ten day stay in often substandard quarantine accommodation. However, it will come too late for many people who have cancelled travel plans.

In a windfall for South Africans, the cost of PCR testing has been revised downward to R500 from R850 as of Sunday following a complaint lodged with the Council for Medical Schemes against private pathology laboratories, alleging the pricing for COVID PCR tests was unfairly inflated. Pricing for rapid antigen tests is said to be next on the list for the Competition Commission. 

On Sunday, a technical glitch caused the National Health Laboratory Service to delay release of a large portion of test results. The glitch meant that initially 18 035 cases were released initially, which rose to over 37 000 after the correction.

The cause was put down to IT difficulties with various laboratories. 

Categories : COVIDTags :

New BA.2 ‘Stealth’ Omicron Variant Discovered

On By ModernMedia
Image source: Pixabay

Scientists have reported identifying a ‘stealth’ version of Omicron that cannot be distinguished from other variants based on standard PCR tests.

The so-called stealth variant has a number of mutations in common with standard Omicron, but it lacks the key genetic change that makes it stand out in PCR tests. This means probable cases are not flagged by routine PCR tests, even though genomic testing can identify it as the Omicron variant.

This distinctive marker had been one of the fortunate features of the new variant, as Tulio de Oliveira, director of the Centre for Epidemic Response and Innovation in South Africa, had explained: “We can detect [Omicron] very quickly, and this will help us to track and understand the spread.”

It is still too early to know whether the new form of Omicron will spread in the same way as the standard Omicron variant, researchers say. However the ‘stealth’ version is genetically distinct and so may behave differently.

The stealth variant was first spotted among recently submitted COVID virus genomes from South Africa, Australia and Canada, but it may already have spread more widely. So far it has been detected in seven individuals.

As a result of this new variant, researchers have split the B.1.1.529 lineage into standard Omicron (BA.1) and the newer variant (BA.2).

“There are two lineages within Omicron, BA.1 and BA.2, that are quite differentiated genetically,” said Professor Francois Balloux, director of the University College London Genetics Institute. “The two lineages may behave differently.”

Whole genome analysis confirms which variant has caused a COVID infection, but PCR tests can sometimes give an indication. About half of the UK’s PCR machines search for three genes in the virus, but Omicron only tests positive for two. This is because Omicron has a deletion in the “S” or spike gene, similar to Alpha before it. This glitch means PCR tests displaying so-called “S gene target failure” strongly suggest Omicron infection.

Informally, some researchers are calling the new variant “stealth Omicron” because it lacks the deletion that allows PCR tests to spot it.

One major unknown is how the new variant emerged. While it falls under Omicron, it is so genetically distinct that it may qualify as a new “variant of concern” if it spreads rapidly. Having two variants arise in quick succession with shared mutations is “worrying” according to one researcher, and suggests public health surveillance “is missing a big piece of the puzzle”.

Source: The Guardian

Categories : COVID PaediatricsTags :

Kids’ Spit Could be a Great COVID Test

On By ModernMedia
Photo by CDC

Saliva samples are easy to obtain and useful for measuring antibodies to SARS-CoV-2 in children, which could improve epidemiological surveillance in school settings. The study followed over 1500 children who went to summer schools in Barcelona last year. The results were published in BMC Medicine.

One of the pressing questions during this pandemic has been to understand children’s susceptibility to SARS-CoV-2 infection and how they infect others. An obstacle to answer this question is that most infections in children are mild or asymptomatic, and are therefore missed. To establish whether an individual has been exposed to SARS-CoV-2 in the past, virus-specific antibodies in blood need to be detected. Measuring antibody prevalence over time in a cohort of children can provide very valuable epidemiological information. However, this requires techniques that are both sensitive and minimally invasive.

In this study, performed through the Kids Corona platform, the team led by Carlota Dobaño, from the Barcelona Institute for Global Health (ISGlobal), and Iolanda Jordan, from Hospital Sant Joan de Déu (HSJD), used saliva instead of blood to measure virus-specific antibodies in over 1500 children who attended different summer schools in Barcelona in 2020, as well as around 400 adult staff. Two saliva samples per participant were analysed, one at the beginning and one at the end of the camp stay, and different antibody types (IgG, IgA and IgM) targeting different viral antigens were measured.

The study found that 3.2% of the participants developed antibodies between the first and second sample, indicating new infections. This is six times higher than the infection rate estimated by weekly PCR screening. “It has been reported that some children can be positive for antibodies despite being negative by PCR, which suggests that they can generate an immune response that prevents the establishment of SARS-CoV-2 infection,” explained Dobaño, first author of the study. It could also be because asymptomatic children have lower viral loads or that their viral clearance is faster.

Furthermore, the analysis shows that the percentage of new infections was higher in adults (2.94%) than in children (1.3%), suggesting differences in infection and transmission dynamics. Finally, contrary to blood tests, asymptomatic people had higher levels of anti-Spike antibodies in saliva, suggesting these antibodies play a protective role in respiratory mucosae. “This means that anti-Spike antibodies in saliva could be used to measure protective immunity upon vaccination, especially in the case of intranasal vaccines,” said senior study co-author Gemma Moncunill.

“We previously demonstrated in other Kids Corona studies that saliva is useful for detecting virus by PCR. With this study, we demonstrate that it’s also an effective and much friendlier way to measure antibodies, making it the ideal sample for children, instead of the more invasive nasal swab,” said Jordan.

Source: EurekAlert!