November 5, 2021 - The first delta plus case in Croatia was detected in Čakovec on Thursday, revealed Krunoslav Capak's deputy Ivana Pavić Šimetin. 

Krunoslav Capak's deputy Ivana Pavić Šimetin confirmed on the HRT show Otvoreno on Thursday that the first delta plus corona strain was recorded in Croatia, reports Index.hr.

"Today, the first delta plus case was recorded in Čakovec. We knew it was at the door. From experience with delta and alpha strains, it will be seen how dangerous it is. What is known so far is that it is somewhat more contagious than the delta strain," she said. 

“It is precisely the smaller proportion of vaccinated people that is conducive to the spread of these new strains,” she added, confirming that the new epidemiological measures will be learned today at a session of the National Headquarters. 

"Among the delta strains that are dominant as causes of infection, the delta strain of variant AY.4.2 is sequenced, which means that the more virulent strain is in our environment and is much faster and easier to transmit," said the director of the Međimurje Institute of Public Health, Marina Payerl-Pal.

She added that the only option for all of us is vaccination, saying that Međimurje is a relatively well-vaccinated region, over 60 percent, but that is still not enough to prevent the spread of the virus in the way we are currently witnessing.

As Index found out last night, the Headquarters will introduce a significantly wider use of Covid-certificates, which are currently mandatory only in health and social care.

But at the moment, well-informed sources reveal that there will not be an extensive application of certificates issued for vaccinations, illnesses, or negative tests, which would include cafes, restaurants, and shopping malls, as announced by some media.

Instead, according to Index, Covid-certificates will be introduced at this stage in all state and public services for employees and users of their services. This means that everyone who works in some state or local institutions will have to have a Covid-certificate to work. Still, citizens who come to public institutions will also have to have this certificate.

Delta + is probably 10% more contagious than Delta

A variant of the SARS-CoV-2 virus called delta is one of the most contagious viruses we know. It is as infectious as chickenpox and is more contagious than the viruses that cause MERS, SARS, Ebola, colds, flu, and smallpox. Delta is also significantly more virulent than the British version known as alpha, which is more contagious than the original Wuhan strain.

As this super infectious variant spreads, it continues to mutate. SARS-CoV-2 is a single-stranded RNA virus, and they mutate faster than double-stranded RNA viruses and DNA viruses. In addition, research has shown that genome size is generally negatively correlated with mutation rate - the larger the genome, the fewer mutations.

In this sense, it is good that the SARS-CoV-2 virus has a large genome composed of about 30 thousand base pairs, so it mutates relatively slowly for single-stranded RNA viruses, slower than the flu. The correlation between genome size and mutation slowness is logical because a virus with a large genome must have a well-ordered check on the accuracy of copying its code. If it did not have that, too many errors would occur in the large genome, and the virus would not be effective - too many viral particles would be created in reproduction that would be scrapped. On the other hand, the flu virus, which is much shorter in RNA, can afford the luxury of being less accurately transcribed and more mutated, and the same is valid for hepatitis C and HIV viruses.

On the other hand, the delta is spreading and replicating so massively due to high infectivity that transcription errors still occur in large numbers. The likelihood of new variants increases, especially in unvaccinated populations.

One of the last variants that caught the attention of health professionals is a variant called AY.1, or delta plus. The reason for the interest is that the Indian Ministry of Health classified it in June as a “variant of concern”. This label indicates that it appears to be more contagious, bind more easily to lung cells, and be potentially resistant to monoclonal antibody therapy, meaning it could break through acquired immunity.

Delta plus has a spike (S) mutation K417N on the protein that delta does not have. This mutation was previously found in some subvariants of the alpha that dominated before the delta and in the beta variant.

James EK Hildreth, executive director of Meharry Medical School in Nashville, told the Washington Post that public health leaders should pay attention to the experiences of other nations, pointing to the devastating effect of the delta in India and the country's decision to label delta plus as a concern.

“We have already seen what happened to the delta in India and how fast it has spread,” he said.

"Why would we think the delta plus variant would be different?" he added.

One reason for concern is the possibility that delta plus would break through the protection created by getting sick or getting vaccinated. So far, we have no explicit confirmation of this concern.

The delta plus variant in Europe was first recorded in March 2021. It has since been discovered in several countries worldwide, including South Korea and the United States. According to the Centers for Disease Control and Prevention (CDC), it currently accounts for only a small 0.1% share of the causative agent among those infected with Covid-19. However, the delta strain is now the cause of 93% of all infections in the United States.

Whether it is more contagious than the delta will be shown over time if its share grows, that is, if it proves to displace the delta. This will take some time because the delta itself is highly contagious, so the advantage of the delta plus variant in terms of contagion is probably not great. For now, it is assumed to be 10 percent more contagious than delta.

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