Data on reinfections

well a warm welcome to today's talk it's uh it's friday the 2nd of july friday evening now a bit of an update from the uk some interesting work from the office for national statistics showing the likelihood of reinfection and the likelihood of disease in a secondary infection with covid19 not related to the vaccine just related to reinfection and the news there is looking fairly promising i think and then we'll look at some news from the united states and europe as time allows i want to start off with some orientation slides first of all just a couple of them here so um australia we're keeping an eye on that at the moment it's on a bit of a knife edge things really could go either way in australia with this delta variant it is a worry and we've expressed frustration that australia has been so slow on the vaccine rollout canada cases are going down now the united states cases are up about 10 on the last week so they are going up in the united states largely due to the delta variant not entirely ireland uh as with europe slight increase in cases in ireland but of course south africa in the united kingdom um unfortunately leading the pack at the moment now big difference actually between south africa and the united kingdom the united kingdom the vaccination rate is high so these cases will transpose into few people getting ill we hope we're pretty sure about that fewer hospitalizations and thankfully fewer deaths south africa where the vaccination rate is low and they're heading into winter which of course is worse anyway it's going to transpose these cases are going to transpose into a much higher percentage of poorly people hospitalizations and and deaths so i'm afraid south africa the third wave that it's entering into now is going to be worse than the previous two that is the way south africa is shaping up unfortunately let's let's hope the vaccination program there can be picked up really really dramatically although not too much signs of that happening anytime soon so i'm a bit concerned about south africa of course we'll be keeping an eye on it so kind of taylor two countries there really uk not so worried south africa really quite quite concerned uh look at europe later on as well definitely increasing cases in europe largely delta uh variant driven as we know united kingdom as we can see the cases are already um high and are still uh still increasing unfortunately now let's not get some information from the office for national statistics now just briefly on prevalence first of all of course office of national statistics it's always slightly out of date week ended the 26th of june england uh the prevalence was one of 260 people in that week um wales one in 450 but northern ireland hundreds uh northern ireland are no longer one in 670 so no lines better scotland unfortunately not so good with 150 people 0.68 of the population infected in that week this increase of course but but of course we know about this this is not new this is the trend unfortunately we've been watching for some time um now um j just to confirm that now if you look on the offensive office for national statistics site of course you get this for all of the the four home countries but um here we see the uh this is the um old-fashioned alpha variant the kent variant and this is the uh delta variant first identified in india so we can see that's down to about 0.05 that's about 0.32 so way higher so this is about 95 or more percent of the infections are now alpha variant sorry are now delta variant with the alpha variant much lower and we can see here that the delta variant was lower on the 16th of may overtook on about the 25th of may and since then the delta variant has just been coming more and more prevalent in terms of percentage of positive cases and um this is an attribute of the virus variant itself and will be repeated in other countries you can just see this this is just happening now office of national assistance covered 19 reinfections as of the 29th of june so it's collected on quite a bit of detail based on the national covered 19 infection survey conducted by the office of national statistics which is large and thorough now i remember way back in february march 2020 wondering about the risk of re-infections and of course we now people we know now people can be reinfected and um but this is showing the level of protection that an initial natural infection gives and it's fairly promising and the other thing is i'm remain optimistic about the longevity of natural infection protection the immunity generated by natural infection and the longevity of immunity generated by vaccines now we'll see that's not a universal opinion later on but it's still i i still hold that and i'm still optimistic about that and so far the data is consistent with with that thinking i've had for some time now but anyway going on to natural reinfection now office of national statistics very precise of course they define what second infection is it's a new positive test 90 days or more after an initial first positive test so this is based on testing which is good or it's a new positive test following four consecutive negative tests so two ways to uh to demonstrate reinfection now office for national statistics say this is rare and they say that secondary infections are milder than the original infections and we know from the coverage symptom tracker data that there's typically fewer infections although we know the infection symptom pattern has changed as we've looked at before much more likely to be headache runny nose sore throat um running those sore throat crowizal of common cold type symptoms um but as the coverage symptom tracker data showed that they're not that common after vaccination and they're milder and they're now in the office for national statistics is showing the same pattern after natural infection and natural immunity so rate of asymptomatic in first and second infection now this did surprise me a bit re-infections of course less likely to report symptoms in other words reinfections more likely to be asymptomatic now first infection um basically they were saying only 21.8 percent of people were asymptomatic but second infection it was 57.1 of people are asymptomatic i must say the rate of asymptomatic in the first infection lower than i thought but that is based on the national survey so that is that is now the data that we have but the key thing is that it's illustrating there is if people are re-infected they're much more likely to be asymptomatic with their second infection than they are with their first infection and also the viral load is likely to be lower now this is measured by the cycle threshold which will we've looked at this before but the strength of infection is measured by a cycle threshold a ct value so what happens is you take your um antigen swab you take the test you run it through the pcr test and that doubles the amount of doubles amount of viral particles every time it does a cycle threshold till it gets to nicely detectable levels so what this means is if it takes fewer cycles to get to detectable levels there's a higher viral load there to begin with if it takes more cycles to get to a detectable level that means there is a lower viral load there to begin with and i'm going to i've kept it writing this down so we get it the right way round so positive positive results with a low ct value with positive results the low ct value of 30 or less so this is episodes of infection with a higher viral load because it takes less cycle thresholds to recognize that the virus is present and these patients are more likely to be ill with a higher viral load and with a higher viral load they're also more likely to be excreting more of the virus and therefore more likely to be infectious so that kind of makes sense and office for national statistics are confirming that now positive results with a high ct value that's 30 or more that indicates a lower viral load less likely to be ill less likely to be infectious and we know that people who are re-infected have lower viral loads and are more likely to be a symptomatic people with first infections are more likely to be symptomatic and have a higher viral load i think i got all that the right way around right um now so initial infections most people have a low ct value higher viral load reinfections high ct value indicating a lower viral load and it's good to have that confirmed by the office for national statistics so in other words can you catch the infection off someone who's got an initial infection yes it's quite likely especially when this delta variant unfortunately can you catch an infection off someone who's been reinfected yes but because they're likely to have a lower viral load because that's been indicated by a higher ct value they're likely to be less infectious so the probability of you getting it is less that is what that is saying now before we go on i'm going to look at the united states in a minute but i just was thinking about this concept of a ct threshold i just came across a rather interesting study um about about ct threshold so that's the study there if you're interested now um the this was 700 hospitalized patients now those that had a ct value of 25 or less in other words they had a high viral load in hospitalized patients i'm afraid 35 of those died so the higher viral load associated with a greater chance of dying those with ct values of 25 to 30 medium viral load their mortality was 17 but those with ct values above 30 ie with a hot with a low viral load so ct values high above 30 with a low viral load their mortality was much less so we see a direct link there between the uh the mortality rates and the higher viral loads in hospitalized patients and patients with higher viral loads lower ct values and we believe exactly the same would be true in terms of infectivity higher viral loads more infection so that was pretty convincing data there clear relationship between viral load as measured by ct value and patients risk of dying in patients that were already hospitalized now i'll show you one more thing on this i think this is from the offer i sort of debated as to whether to show you this or not but i think i think you can probably cope if i if i can you most certainly can let's have a look at it now the office for national statistics they come up with some amazing graphics so here we have what we have here is um this is lower viral load towards this end and uh higher viral load towards this end so the higher viral loads lower ct value the lower viral loads higher cycle threshold values so lower viral load higher viral load so what we see with initial infections is the greens are asymptomatic so this is the distribution of viral load in initial infection and we notice there's not a completely clear correlation there between uh the the symptomatics and the asymptomatics slightly more symptomatic with a high viral load yes but some symptomatics with very uh low viral load an initial infection quite interesting but reinfection we see this cluster way down here at the lower viral load with with few very few patients up here with a higher viral load but we notice there's nothing like a one-to-one correlation between being symptomatic and viral load so i thought that was a really quite uh i've actually never seen a graphic quite like that before so um i thought that one was um really pretty clever so i thought i'd show it to you anyway the reference for that is on the um is on the office of national statistics site that we looked at now moving on to the united states let's have a quick look at the data from from the states here um so infections are actually up about 10 on the week um unfortunately on the seventh so the seven day rolling average this is always a bit out of date of course but the seven day rolling average from the uh cdc data is nine point one percent i think it wasn't yeah nine point one percent higher uh this seven days than the seven days previous to that so um as we've been expecting for some time infections are starting to increase in the states so slight increase in infections in the state still nothing like it was of course and if we look at deaths in the states they are continuing to go down which is is good news but if the cases continue to go up because of the relatively large number of people and vaccinated in many parts of the states um deaths will go up towards the end of summer and into um and into the the fall into the uh the autumn time i'm afraid that is probably what is going to be happening uh in in the states um because we know the vaccination program's continuing but not as quick and it's patchy this is the thing so the united states cases up 9.1 percent on the past seven days first time there's been an increase for quite some time 25 of these new cases are delta variant now in the states we are very variance of interest variance of concern variance of high consequence and of course the delta variant is still in the variant of concern category thankfully we have no variance of high consequence let's hope we never do because that would be bad because they're variants of high consequence right adults with at least one dose of vaccine now alabama is about 49 to 50 percent adults with at least one dose wyoming only 50 way below the national average virgin isles 49 louisiana 48 mississippi trailing up the rio in the united states at 46 of adults with at least one dose the delta variant will increase fairly quickly in these states the delta variant will become the prevalent the most prevalent variant in the united states over time but these are the states that risk the lowest vaccinated up step lowest vaccinated states and remember that's adults with at least one dose so doubly vaccinated going to be way less than that and we know that two doses of the the vaccine are needed to get any significant benefit from protection against the delta variant if you've only had one dose of the fisa vaccine for example your protection against the delta variant from symptomatic infection is only about 35 bunking up to about 88 if you've had two doses and of course even if these states start vaccinating like bilio now there's going to be a bit of a delay because it takes three weeks after the second dose now the correlation between the thousand worst counties for where 30 of adults have got one dose or less and the increase in cases is greater so there's a clear correlation between the thousand counties with the lowest uptake of adults being vaccinated and the highest increase of infections so check out the uh the cdc data so pretty clear pattern emerging in the states of the well vaccinated and the well what we can only say poorly vaccinated area and it's not through shortage of supply if this was in south africa they would be curing up around the block for these vaccines absolutely and virtually everywhere else in the world that would be the case actually so really unvaccinated friends that you have in the states i think you know the best thing to do for them to increase their probability of survival and wellness to reduce their chances of morbidity and mortality now uh briefly we'll do a bit on europe so things as we said going up in europe it's been going down for 10 weeks it's just started going up now wh hans klug in europe new wave of the who european region unless we remain disciplined but it's already happening social mixing is increasing travel is increasing easing of restrictions is increasing delta variant is increasing spain it's in the unvaccinated younger people russia the deaths are going much higher that was 48 hours ago i'm not sure what the last 24 was uk cases 27 125 last 24 hours 24 hours before that 20 6 000. it's going up in the uk really quite uh quite dramatically in fact we'll just have a look at that now i think here we see the uh the the the uk so the vaccination numbers are going are going well so that's good uh but but if we look at cases if we have the technology well no question no question i mean this really does constitute a third wave in terms of cases but as as we've said because of the vaccination rates in the uk health care admissions to hospital up a bit yes which we would expect total number of people in hospital uh up a little bit but nothing like as much as they would be without the uncoupling between the cases and the hospitalizations as a result of the vaccination and likewise deaths in the uk i mean it's still 116 people in the week but that's mercifully low compared to what it has been so we might see a small increase in deaths in the uk but we are really hoping it's going to be small all adults over the age of 18 need to report for vaccination in the uk as soon as possible the vaccines are there go and get them now um this applies to everywhere really but the um this idea that we're going to have a sort of a liberation day on the 19th of july in the uk it really is i've been thinking about this and it really is simplistic i was just i was just thinking this is such a simplistic idea nothing is going to change between the 18th and the 19th and the 20th of july it's just a date and i was thinking about this and then i heard david nabarro talking about now dr david nabarro um in my view should immediately be appointed uh head of the world health organization he's been a medical doctor all his life highly qualified highly experienced as a highly experienced teacher he just knows what he's talking about um pity is not in charge i think but there you go that's where a rat um but anyway david nabarro said this um we do have to be prepared for the inevitability that virus viruses will continue to be a problem for us so it's not going to go away all of a sudden according to dr navarro we're going to have to really seriously contemplate continuing to practice some degree of physical distancing some degree of mask wearing some degree of hygiene so this idea of liberation day where all of a sudden the clock ticks over from midnight to a minute past midnight and everything goes back to normal it's not even simplistic and dr nabarro is saying that's not the way it works some degree of protecting those who are most at risk as long as there are these nasty viruses around whether or not we're vaccinated so in contrast it really has to be said dr nabarro is in contrast here to what the centers for disease control is saying where you're what you're allowed to do depends on your vaccination status david nabarro are saying no we need to have some low-cost ongoing interventions it makes people very angry because they want to be able to stop being careful but it's my advice and it's just based on studying these things over many years i mean quite a few years you're longer than me but of course specializing in this sort of field is that it's not a cool thing to ditch our preventative measures uh on a particular date because we hope that's going to be associated with less risk the risks are going to stay so it's ludicrously simplistic to say that we have a freedom day it's uh much more of a political statement and we'll take dr nabarro's medical statement as being more accurate so um oh um yeah you just final news on the couple of maybe things on the uk uh uk vaccine boosters in autumn interesting it looks like the well the government are planning for it all adults over 50 nhs and care staff anyone who qualifies for a flu jab will probably be offered a third dose in autumn professor anthony harding joint committee on vaccination immunization we're worried about people who have had their vaccine earlier on we want to make sure they have a booster in time for winter we do know from other vaccines that immunity wanes quicker in older people than younger people so he seems concerned here that the immunity is going to wane and we're going to need a booster because if you had a vaccine like six months ago you're gonna need another one now because the immunity is dying down well i see no data that that is the case i really don't see any data that that is the case i actually think is i don't i don't think he's right on this now if of course immunity does start to decline then sure we're going to need to boost the dose now having said that with the new variants and of course these booster doses are not going to be a new variant tweaked vaccine they're going to be an old type vaccine probably an mrna vaccine for the boosted doses or maybe a protein based virus vaccine potentially um i think that's the novovax one isn't it i think but the additional vaccination even though it's with vaccines that were designed for the original wild type virus if you have another dose of that will that will increase your immunity to the new variants even though these are not going to be tweaked vaccines that are going to be ready for this autumn so i think his fear there that immunity is going to wane by autumn is unfounded but if if he's thinking that a third dose of the vaccine will give even additional immunity over that which we're going to retain in my view then that's fair enough and this seems to be the way that russia's going as well uh they seem to be going for an annual booster in russia which i thought was interesting now just briefly uh we can't cover everywhere of course but africa is a concern as well it really is quite a concern so uganda population 45 million president umari public holiday last friday for the nation to pray for um relief from the pandemic getting about 20 000 cases a day and this is with virtually well i can't say virtually no testing but massively limited testing they've had about two million infections increased holiday travel and they have the delta variant deaths 126 no not most aren't recorded president mr mi7 they said that actually in his talk he said most deaths aren't recorded they've gone into a 42 day lockdown restrictions on movement roadblocks at district borders covered relief funds were mismanaged last year meaning a lot of poor people like bangladesh are really going to suffer during that is one heck of a long lockdown so as in bangladesh the real fear is people are going to go hungry as a result of this in kampala in uganda of course lack of beds lack of oxygen uh lack of oxygen equipment lack of ppu lack of gloves lack of ambulances and basically lack of uh everything we used to sometimes send students to i won't mention particular african countries but um basically we always told them to take boxes of their own gloves just for their own personal protection they just weren't available this is the sort of minimal financing level that many of these hospitals run on unfortunately medical fees in uganda are high uganda's private hospital cash down payments of three thousand dollars need to get in way way beyond the average salad annual salary of most people astrazeneca remember the country is 45 million and they've had what one and a half percent of the population with one dose 834 000 not enough africa's got 1.3 billion people overall 18 of the world's population 2 of the vaccine doses you know we really need to reflect on this don't we but not for too long because we need to act on it pretty quick other parts of the world indonesia population 270 million java and bali are locked down for two weeks limited testing outside jakarta and again we see increasing cases so some parts of the world with good vaccination rates doing well um ironic that people in indonesia and uganda are absolutely desperate for vaccines and are curing around the clock if they get the chance of a vaccine whereas in other parts of the world people are not taking up the vaccines that are available so um maybe a few things to reflect on there nothing we haven't talked about before global inequality fairness all the lack there of things to think about anyway that's some interesting information there so basically good news on reinfection and of course we we believe that the immunity generated by the vaccine is even better than the immunity generated by um generated by natural infection and we've looked at the fact that people that are vaccinated are much much much much much much much safer symptomatic disease is going to be less symptoms or less for less duration so there we go um that's us for today a bit longer than i intended but if you stay to the end thank you for staying to the end and thank you for watching

Channel: Dr. John Campbell

Views: 260,641

Keywords: physiology, nursing, NCLEX, health, disease, biology, medicine, nurse education, medical education, pathophysiology, campbell, human biology, human body

Id: gGllOW3zo1k

Length: 27min 43sec (1663 seconds)

Published: Fri Jul 02 2021