Scotland is experiencing another wave of Covid-19 infections as cases of two Omicron variants increase, a public health expert has said.
Professor Linda Bauld said the Omicron sub-lineages BA.4 and BA.5. are part of the reason for the increase in cases and a "small but not significant" rise in the number of people in hospital.
However, she said that vaccines are working well in the vast majority of people and are making a difference between the risk from infection and the risk of severe disease.
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Latest data from the Office for National Statistics (ONS) showed that around one in 40 people in Scotland had Covid-19 in the week ending June 2, up from one in 50 the previous week.
Professor Bauld, a professor of Public Health at the University of Edinburgh, told BBC Radio Scotland's Good Morning Scotland programme: "I think it's pretty clear to me from some of the data we've seen that we are certainly in another wave of infection, if not already it will be soon and that certainly seems to be the case in a number of countries, and that is not a big surprise because we did anticipate we would have a rising level of infections every three or four months potentially, that's what international colleagues have said.
"It might be surprising to people though because it's the summer, and they're used to hearing from us (that) the weather is better so people are more outside and therefore we reduce the risks through our behaviour.
"That's true, but what we've got is Omicron and a different type of it, BA.4 and 5 - there's these Omicron sub-lineages which seem to be rising in number in the UK and I think that's part of the explanation why we're beginning to see more cases, and we have seen a small but not significant rise in the number of people in hospital as well."
Professor Bauld said that vaccines offer good protection against severe disease, but she thinks it likely that the offer of a booster jab may be extended to a wider range of groups in the autumn, beyond what the Joint Committee on Vaccination and Immunisation (JCVI) has recommended.
The JCVI is recommending care home residents and staff, frontline care workers, those aged 65 and over and adults aged between 16 and 64 who are clinically vulnerable should be given another dose of Covid-19 vaccine in the autumn.
Professor Bauld said: "Your protection doesn't fall off a cliff, it wanes gradually. Your protection against getting infected actually wanes pretty quickly and the vaccines are not sterilising so they are not protecting us against the risk of infection.
"Your risk of severe disease... I think even beyond months after your dose, you may not be having such a robust antibody response but other bits of the immune system, B and T cells, are still working against getting very unwell.
"In older groups whose immunity doesn't last as long the waning looks quicker. Will we have more people vaccinated in the autumn? Yes, for the over 65s and immuno-supressed, that's what JCVI says. Whether they will extend it to those of us in our 50s and other groups is something they are reviewing.
"If you were to ask me what I think, I think it's likely they will change that eligibility, but we will wait to hear.
"We need to give people as much protection as we can and we are, like influenza, going to have I think regular vaccinations in the future for Covid-19, not for everyone but for many groups."
