Coronavirus statistical update: Indian variant rings alarm bells

The Indian variant, or one version of it, has become the UK’s enemy no 1 in the battle against the coronavirus, spreading at a worrying rate and threatening to derail the roadmap schedule out of lockdown restrictions in June. It has not so far been detected in East Sussex. Text by Nick Terdre, research and graphics by Russell Hall except where noted.

Alarm bells are ringing at the rapid increase in Covid-19 infections due to the Indian variant B.1.167.2. Public Health England reported that up to 19 May a total of 3,424 cases had been confirmed, up from 1,313 a week before. According to health secretary Matt Hancock speaking in the Commons on 17 May, there were 86 council areas with five confirmed cases or more, and presumably more now.

B.1.167.2 was only designated a variant under investigation (VuI) on 21 April and escalated to a variant of concern (VoC) on 6 May. Two other versions of the Indian variant have been identified, B.1.167.1 and B.1.167.3, both of which are classed as VuIs and are not associated with many infections.

The most common strain in the UK remains the Kent VoC B.1.1.7, of which a further 7,066 cases were confirmed in the week to 19 May, taking the total to 249,637. That is fewer new cases than in the previous week. While widespread across the country, the Kent variant is considered to be under control. Since the second wave of the pandemic reached its peak in January, it has been reduced to very low levels: on 13 May the government reported that the seven-day figure for all new cases was 2,061, for hospital admissions 98.1 and for deaths 7.7.

The Kent and the Indian variant both display a higher binding affinity to the ACE2 receptor on the surface of our cells than the Covid strain which led to the first lockdown last year, but according to Prof Ravindra Gupta of Cambridge University the Indian is more ‘fusogenic,’ which makes it easier for the virus to enter our cells.

But the sudden emergence of this variant has caused a lot of speculation: is it significantly more transmissible than the Kent variant? Is it resistant to the current vaccines? Does it cause more serious illness? And of course, will it derail the removal of the final lockdown restrictions scheduled for 21 June?

Vaccines are effective

Some reassurance has come on one issue – vaccine resistance. A new PHE study examining vaccine effectiveness for the Indian and Kent variants found that the Pfizer/BioNTech vaccine was 88% effective in preventing symptomatic disease from the Indian variant two weeks after a second dose was given and 93% effective for the Kent variant.

Two doses of the AstraZeneca vaccine were 60% effective against the Indian variant and 66% against the Kent. PHE suggests that the difference between the vaccines may be due to the fact that AZ was rolled out later than the Pfizer, so many more of the study participants who had the AZ vaccine had had their second dose more recently, and it takes longer to reach maximum effectiveness.

Given a longer period the protection AZ provides is expected to increase. PHE concluded that its study shows that “two doses of the Covid-19 vaccines are highly effective against the B.1.167.2 variant.”

There was however a clear difference in effectiveness against the two variants after one dose of either vaccine: both were only 33% effective against the Indian but 50% against the Kent.

Clarity over the transmissibility of the Indian variant is however far from being achieved. Early PHE data indicates that people infected with B.1.167.2 go on to infect between 11.1% and 14% of their contacts (the so-called secondary attack rate), while for those with B.1.1.7 it is between 7.9% and 8.3%. But it is not yet clear if this is due to it being more infectious or down to social factors such as contacts of B.1.617.2 cases having a higher risk of exposure.

In its meeting on 13 May the government’s advisory group Sage stated that, “It is a realistic possibility that [B.1.167.2] is as much as 50% more transmissible” [than the Kent]. In practical terms “50% more transmissible” translates into exponential growth, while 20% or 30% is much less than that. The phrase “realistic possibility” is used to indicate that there is a 50% chance the statement may be true – but the same chance it may not be.

Insufficient data

Experts suggest there is insufficient data at present to draw any firm conclusions. While the hotspots of Bolton and Blackburn may suggest high transmissibility, there are other areas where the variant has gained a foothold but growth rates have been much lower.

On the Today programme on 21 May, Prof Neil Ferguson of Imperial College and a Sage member described a scenario in Bolton with the variant being introduced (by travellers arriving from India) principally into people of Indian ethnicity, with a higher chance of living in multi-generational households and often in deprived areas with high-density housing – conditions ripe for a rapid spread of infection regardless of the variant’s transmissibility.

He added that while the virus appeared to have a significant growth advantage, recent data appeared to indicate that the magnitude of that advantage had dropped a bit, and the curves were flattening a little.

It has also been reported that the spread of the Indian variant could have been facilitated by a failure of the government’s Test & Trace system to provide full data to local authorities on positive cases detected in their areas. Bolton, however, was not one of these, though Blackburn was, along with seven other areas.

Tardy government action may have helped the spread of the variant. Whitehall has been accused of failing to act on early signs of growing numbers of B.1.167.2 cases in Bedford, now one of the leading hotspots. It has also been accused of allowing the Indian variant to propagate in greater numbers by delaying putting India on the red list of travel destinations for political reasons.

While the issue of transmissibility remains unresolved, the Indian variant appears to be well on the way to taking over from the Kent as the dominant strain of Covid-19 in the UK as it extends its reach to hitherto unaffected areas.

There is no evidence yet that it causes more severe illness or is responsible for more hospital admissions or deaths, but health experts warn that these effects may yet occur if it infects greater numbers of older people.

Twin strategy

Meanwhile the spread of the variant is being combated through the twin strategy of surge testing and surge vaccination. Surge testing is aimed at testing as many residents in a locality as possible to identify cases of  asymptomatic infection and encourage them to isolate. It also provides important feedback on the prevalence of the virus in an area. (Widespread testing of wastewater is also under way as a means of early detection of infection spikes.)

‘Surge vaccination’ – a new entry in our coronavirus vocabulary – relies on the idea that the higher the degree of vaccination of a population, the more the advance of the virus will be contained. It is effectively the advice given by the Joint Committee on Vaccination and Immunisation, and accepted by the government, that vaccine uptake should be promoted among unvaccinated members of the priority cohorts 1 to 9 (over 50s and clinically vulnerable), that the interval between doses should be reduced from 12 to eight weeks particularly in areas where B.1.167.2 is a major threat, and that the vaccination programme should continue to be rolled out as quickly as possible.

In Bolton measures such as deploying two vaccine buses, extending pop-up sites and engaging with local communities to encourage those who have not yet had the jab to do so are being implemented. Similar actions are being taken in Blackburn and other affected areas.

An additional 6,000 doses were given in Bolton over the weekend of 15/16 May, according to council leader David Greenhalgh. Cases were still rising, he said, but primarily among people in their 20s or younger. There had been no increase in hospital admissions or severe illness, though more recently an increase in hospitalisations has been reported.

Surge testing is also being stepped up, with enhanced contact tracing, additional mobile testing units in action, door-to-door testing being offered and extra PCR test kits made available at community testing sites. In Bolton a 100-strong Surge Rapid Response Team has been deployed, and the army is providing planning and logistics support.

Handy guide

PHE’s interactive map above provides a handy guide to areas in which the Indian variant has been confirmed. According to the Sanger Institute, in the week ending 15 May cases with this variant were found in 151 local authorities (the data excludes samples from recent travellers, surge testing and special studies), 57 of them with five cases or more. Within the past week surge testing has been introduced in seven areas in London and Hampshire in addition to the 13 across the UK in which it was already being used.

On 21 May the government updated its guidance advising against non-essential travel in and out of eight areas where B1.167.2 is spreading fastest – Bedford, Blackburn with Darwen, Bolton, Burnley, Kirklees, Leicester, Hounslow and North Tyneside – but failed to inform anyone. When the guidance became known, it caused such a furore among the local authorities involved that the recommendation was changed to “minimising” travel.

Whether Step 4 of the roadmap, the lifting of the final lockdown restrictions, will be able to go ahead as planned on 21 June is an open question. While prime minister Boris Johnson has recently claimed there should be no problem, many health experts feel it is too early to make a decision.

No cases of B.1.167.2 have been detected in East Sussex so far, but there are a handful in West Sussex and cases have been detected in Brighton & Hove and most parts of Kent.

In his weekly column dated 20 May, the East Sussex director of Health Darrell Gale notes that East Sussex has the lowest seven-day Covid case rate – 12 per 100,000 inhabitants – but says the picture is very contradictory: there is “satisfaction in the low number of cases and concern about the escalation of rates caused by new variants.”

As people enjoy the recently introduced freedoms, he urges them to apply sensible measures, including taking regular tests, “hands, face, space,” and getting the jab.

 

This article was amended by Nick Terdre on 26 May 2021.

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