Covid is back with a vengeance – facing down BA.2 as it runs amok

A new variant and waning vaccine efficacy are behind the current Covid surge

Professor Luke O'Neill. Photo: Ruth Medjber

Luke O'Neill

Covid-19 came back into our sights with a vengeance last week with the HSE saying it was ‘really struggling’ because of the surge in cases. By Thursday, there was a 29pc increase in new cases over the previous week, with more people ending up in hospital with the virus .

This creates pressure on the health service because people with Covid-19 must be treated on a special Covid ward. What this means on the ground is that it’s not Covid-19 per se that’s putting pressure on the system. It’s the lack of facilities to handle the Covid-19 cases. Covid-19 is, as ever, revealing a deficiency that was already there, just like flu does every winter. In addition, 5,200 staff are out with Covid-19 adding to the pressure.

One consequence of all this is that various medical procedures are being cancelled. Our hospital system is therefore yet again feeling the strain.

Why is this happening? There are two likely reasons. Firstly, there is a new variant running amok called BA.2. This is 30pc more transmissible than its sibling, the Omicron variant, which was already 70pc more transmissible than previous variants. BA.2 is sweeping up all those who didn’t catch Omicron. As well as being more transmissible, it also has a shorter incubation time, which means people become infectious more quickly after infection. BA.2 is therefore the most infectious variant we have seen, and is spreading like wildfire, not only in Ireland but all over Europe.

Mercifully, however, the vaccines are largely holding up against it. If they weren’t, our hospitals and ICUs would be full of Covid-19 patients. We are lucky BA.2 didn’t come along at the start of the pandemic. Because natural infection with previous variants and vaccines provides protection, we’re not seeing a huge increase in severe disease and therefore no increase in ICU admissions for now.

This surge is likely to peak soon as most of those who are susceptible become infected, and we are entering late spring/early summer. This means we are all outdoors more, or we are happier about keeping windows open.

Because Covid-19 is now clearly a seasonal virus that spreads indoors, this surge will abate in the coming weeks. It remains important, however, for people to still wear masks in crowded indoor settings — for example on public transport. This will help decrease spread and even if masks aren’t perfect, they lower the dose of virus spreading and so give rise to less severe disease in those infected by someone who is infectious but wearing a mask.

The second reason for the surge is the waning of the vaccines. There is evidence of some waning of immunity against Omicron and BA.2, especially in older people. This means taking the third shot when called, or the fourth shot for those who are vulnerable or older, is very important. This will restore protection in these next few weeks as we emerge from this surge.

Masks and vaccines and people staying home if they have symptoms will help decrease the pressure on our healthcare system. If you have symptoms of a cold or flu you can assume it’s the BA.2 variant, given how widespread it is.

David Nabarro of the WHO said last week that we can expect surges every three or four months. Covid-19 won’t be going away. There are likely to be epidemics in the future, particularly as we come into autumn/winter. This might make you say ‘Will we ever escape this?’ The answer sadly is no. We have to learn to live with it. The good news, however, is we know how to mitigate against this virus.

What’s actually happened is a new virus has come along to infect humans. Just like in the past influenza came along, or TB or HIV. Like those viruses, SARS-CoV-2 is another virus to jump from animals into humans and stick. In medical textbooks of the future in the chapter on infectious diseases there will be a section headed ‘SARS-CoV-2 and Covid-19’ which will give the clinical characteristics of the disease but also state that Covid-19 is preventable with vaccines, and treatable with antivirals. This is why we needn’t be too fearful as we look to the future. But we do need to be prepared, especially if a more malign variant should come along.

What will that future look like in terms of living with Covid-19? First of all, our best weapon will continue to be vaccines. Next-generation vaccines are coming, including vaccines that will work against any coronavirus (so-called pan-coronavirus vaccines). Companies are also testing vaccines that will work even better than the ones we have. These might not only protect you from getting severe disease like the current vaccines, but will help protect you from getting infected in the first place and thereby decrease transmission. This is because they will not only bring out the immune troops in your lungs, but also in your nose and upper airways, so if any virus gets in there, it will be killed quickly.

These vaccines include intranasal vaccines (including the AstraZeneca vaccine which is being reformulated). Because they are applied to the nose, they will elicit a strong immune response there, as well as deeper in your body. We eagerly await these so-called mucosal vaccines.

We can anticipate vaccines being deployed again in late summer/early autumn, for people who are vulnerable or older. This will be just like the flu vaccine. If the new vaccines are available by then, it’s likely that they will be deployed, but current vaccines will still give protection.

The second key weapon we have is ventilation. We need to make sure that everywhere indoors where crowds gather, there is adequate ventilation. Just like we made sure there was clean water to stop the spread of cholera and dysentery, we now need to clean the air, using ventilation. That will be a great help in winter, with the additional bonus of limiting the spread of flu.

Surveillance will also be important, to spot if a new variant comes along and to act quickly. Speed is essential as we saw at the start of the pandemic. If a new variant should arrive, we need to act fast to limit it. This might involve mask mandates, or some limited restrictions being introduced. Let’s hope these won’t be needed, but we need to be prepared for the next variant which will surely come.

One other important issue we need to consider is long Covid.

There is a real risk that the numbers of people with persistent symptoms after infection will grow, especially following the current surge. We need resources in the healthcare system to take care of them, and research to come up with better ways to diagnose long Covid and hopefully treat it.

What all of this means is we know what to do when the surges happen. We just need to make sure we are ready. Because one thing is for sure, Covid-19 will keep coming back, but it’s up to us to make sure it can be quickly contained when it does.

Luke O’Neill is professor of biochemistry in the school of biochemistry and immunology at Trinity College Dublin

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