Large UK Study Delivers Big Blow to Covid Herd Immunity Thesis, Raises Concerns About Vaccine Strategies
From early on, we’ve raised concerns about how much protection the much-awaited Covid vaccine would provide, since contracting the other common coronaviruses confers only limited immunity: on the short end, about six months for the common cold and on the long, 34 months for MERS.
A new large-sacle study in the UK confirms these worries. Tests of over 350,000 people determined that the percentage with Covid antibodies has fallen in the last few months, which is alarmingly at odds with the fact that more people cumulatively have contracted the disease over time. The falloff in antibody levels is similar to that of the common cold, meaning consistent with being infected producing only short-term immunity. Needless to say, this result is at odds with the fantasy that merely having enough people get sick would solve the Covid problem eventually.
Moreover, the study data also suggests that those who got asymptomatic cases had their antibody levels fall off faster than those who had more serious cases.
These results are an early warning that antibody-based vaccines will only offer months of protection. Mind you, antibodies aren’t the only defense that the body mounts against Covid. In fact, some scientists were already warning that the focus by most Covid vaccine developers on antibody responses was misguided, and targeting T-cells was a safer bet. For instance, from Berkeley News last month, summarizing a paper in Vaccine:
More than 100 companies have rushed into vaccine development against COVID-19 as the U.S. government pushes for a vaccine rollout at “warp speed” — possibly by the end of the year — but the bar set for an effective, long-lasting vaccine is far too low and may prove dangerous, according to Marc Hellerstein of the University of California, Berkeley.
Most vaccine developers are shooting for a robust antibody response to neutralize the virus and are focusing on a single protein, called the spike protein, as the immunizing antigen. Yet, compelling evidence shows that both of these approaches are problematic, said Hellerstein, a UC Berkeley professor of nutritional sciences and toxicology.
A better strategy is to take a lesson from one of the world’s best vaccines, the 82-year-old yellow fever vaccine, which stimulates a long-lasting, protective T-cell response. T-cells are immune cells that surveil the body continuously for decades, ready to react quickly if the yellow fever virus is detected again.
“We know what really good vaccines look like for viral infections,” Hellerstein said. “While we are doing phase 2 trials, we need to look at the detailed response of T-cells, not just antibodies, and correlate these responses with who does well or not over the next several months. Then, I think, we will have a good sense of the laboratory features of vaccines that work. If we do that, we should be able to pick good ones.”
Using a technique Hellerstein’s laboratory developed and perfected over the past 20 years that assesses the lifespan of T-cells, it is now possible to tell within three or four months whether a specific vaccine will provide long-lasting cells and durable T-cell-mediated protection.
Needless to say, the press reports on the so-called Real-time Assessment of Community Transmission findings from the Imperial College were sober.
Some argued that the survey was less than ideal by not repeatedly testing the same individuals, but the results were so marked over a large population that it seems unlikely that the general conclusion is invalid. The researchers tested groups of 100,000 each round, chosen at random, from 314 “local authorities”. The first test period, from June 20 to July 13, found that 6.6% of the subjects had Covid 19 antibodies. The latest test, from September 15 to September 28, showed the level had dropped to 4.4%.
Imperial College London’s Covid-19 prevalence study is relatively bad news:
Antibody response present in 6% of the English adult population from June 20-July 13
Fell to 4.8% by July 31-Aug 13
Fell to 4.4% by Sept 15-28https://t.co/2t9aMfZObU
— Mike Bird (@Birdyword) October 27, 2020
The proportion of people in England with coronavirus antibodies dropped by more than a quarter in the space of three months, researchers have revealed, fuelling concerns over reinfection….
Prof Wendy Barclay, chair of influenza virology at Imperial College London and co-author of the report, said it was not yet known what level of antibody is needed to protect someone from infection or reinfection with Covid-19, but experiments suggested it could be around the same level as the antibody test’s threshold of detection…
Some have raised the possibility that other components of the immune system might continue to offer protection even if antibodies have waned – such as T-cells, which can kill infected cells, or B memory cells, which can rapidly produce new antibodies. However, the team said it is too soon to know if that is the case, or for how long that protection might last, while it is difficult to measure levels of such T-cells.
“The fact that people get reinfected regularly throughout their lives with seasonal coronaviruses [that cause common colds] suggests that the immunity, whether or not it is antibody mediated and/or T-cell mediated, probably isn’t very long-lasting,” said Barclay, who added that the team suspect the body reacts to infection with the new coronavirus in a similar way….
The team said the lack of reinfections could be because it is difficult to confirm such cases – but it may also be that not enough time has passed for antibody levels to have declined to the point where most people are susceptible to reinfection.
Levels of protective antibodies in people wane “quite rapidly” after coronavirus infection, say researchers…
“Immunity is waning quite rapidly, we’re only three months after our first [round of tests] and we’re already showing a 26% decline in antibodies,” said Prof Helen Ward, one of the researchers.
The fall was greater in those over 65, compared with younger age groups, and in those without symptoms compared with those with full-blown Covid-19.
The number of healthcare workers with antibodies remained relatively high, which the researchers suggest may be due to regular exposure to the virus.
The UK’s Health Minister, Lord James Bethell, called the study a “critical piece of research” that could help inform the British government how to take the right action to control the spread of Covid-19.
“It is also important that everyone knows what this means for them — this study will help in our fight against the virus, but testing positive for antibodies does not mean you are immune to Covid-19,” Bethell said in a news release….
Dr. Claudia Hoyen, who specializes in pediatric infectious diseases at University Hospitals of Cleveland, thought the study was interesting and encouraging, since it suggests that at least where antibodies are concerned, this coronavirus acts like other coronaviruses…
“This study is really like the first piece of the puzzle that actually gives us the indication that, yes, these antibodies don’t seem to stick around for everybody,” Hoyen said. “At least in this case, this virus is sort of acting like we can predict, which is a good thing because everything about this virus has been so off the wall.” Hoyen said the study also “cements the fact that we’re going to be in masks for a while.”…
“I think the sooner we resolve ourselves to the fact that this is what we have to do to get through this, we can accept it and move on. This data clearly shows that your antibodies go away. So just because you have had it once, doesn’t make you’ immune and it also means you can be contagious again.”
Needless to say, this doesn’t change my plans. But I wonder what two years of restricted activities (that looks to be a conservative estimate) is going to produce recreational PTSD. Will I ever feel comfortable in an old-normal bar, or restaurant, or conference?
Needless to say, that’s far from the biggest worry. The press reports tonight on protests in many cities in Italy over the latest round of Covid restrictions. When governments act so that meaningful numbers of people lose income and suffer more burdens (like having to care for kids at home when they were formerly at school) without making concerted efforts to ameliorate a lot of the damage, it should come as no surprise that they don’t want to go along. But the West seems incapable of getting out of its neoliberal underwear.