UC San Diego Infectious Disease Modeler Warns Of New Variant Spread In San Diego County
Speaker 1: 00:00 Justice San Diego begins to enjoy a small relaxation of the COVID lockdown. A group of local researchers has issued a stark warning, a presentation at the County board of supervisors on Tuesday outlined how increased transmissions even with a robust vaccination program could cause COVID cases to skyrocket and hospitals become overwhelmed. The concern is that because the more infectious Corona virus variant first discovered in the UK is likely to become the dominant strain here very soon. This is not a good time to increase social contact at restaurants or other venues. Joining me is the researcher who made yesterday's presentation to the supervisors, Natasha Martin and infectious disease modelers. She's associate professor in the division of infectious diseases and global public health at UC San Diego. And Natasha, thank you so much for speaking with us. Speaker 2: 00:57 Thanks for having me. Why Speaker 1: 00:59 Is the UK variant expected to become the dominant strain here? There are still fewer than 100 cases identified. Isn't that right? Speaker 2: 01:08 That's right. Uh, what we can see across places where the [inaudible] variant has emerged, um, such as in the UK and, um, in other places in Europe, once that strain was identified, it quickly became the dominant strain because it is estimated to be 50 to 70% more transmissible than previous strains that emergence and domination of that strain meant that in places with that, which have seen the strain become dominant, have experienced surges of infections. Although the prevalence of the [inaudible] variant is estimated to be relatively low currently in San Diego at 5%. Again, because of this increased transmissibility, we anticipate that it will become the dominant strain within a matter of weeks. The question is not whether it will become the dominant strain, it will, but how long it will take. And whether we're we have the capacity to reduce transmission and prevent it becoming a situation that overwhelms our hospital resources Speaker 1: 02:09 Say more transmissible. Does that mean masks are not as effective? Speaker 2: 02:14 Yes. The evidence that we have is that individuals who are infected with the [inaudible] strain have a higher level of viral load than other strains, which means that they are more infectious and more likely to transmit the virus to others. And that means that we want to be particularly adherent to wearing masks properly. And at all times, if possible, when I'm in the company of other individuals to prevent this more infectious and more transmissible strain from spreading to others. Speaker 1: 02:46 And that means, uh, social gatherings should be avoided. Speaker 2: 02:50 Yes, I think in this period where we, although we've seen a decline recently in transmissions after the new year's and Christmas surge, which is the concern is that as this variant becomes more dominant and more prevalent in our community, just because of the increased transmissibility, we will very likely see an increase in cases due to that, even if behavior does not change. So what we want to do is anticipate that this might happen and re take all the measures possible in terms of masking social distancing, to reduce transmission, reduce the circulation of this more transmissible, variant, and bias time to vaccinate individuals and increase coverage of vaccination to achieve herd immunity. Speaker 1: 03:32 You also say there are indications that the strain is more lethal. What can you tell us about that as evidence Speaker 2: 03:39 There's some preliminary data which emerged from the scientific body, which advises the UK government to indicate that in the UK, this strain may be potentially 30% more lethal than other strains. I think we still need more evidence, but it's an added consideration when we're thinking about the potential surge that could occur due to the, the strains increased transmissibility. We then also need to consider that those who become infected with his strain may be more likely to be hospitalized and more likely to need intensive care and more likely to die. So, you know, this is a particular concern in terms of the expansion of this, this variant, Speaker 1: 04:18 The modeling that's been done by state public health officials that led to the end of the stay at home order is based on a trending decline in cases and hospitalizations. Doesn't that indicate that the variant is not taking hold the way you project. Speaker 2: 04:33 So that modeling just takes into account the estimated transmission rate or effective reproduction number at, at a given moment in time. So it incorporates our understanding of on average, how many people are being infected by an infected individual today. It does not take into account the fact that there are changing variants, that there may be variance in some places such as the [inaudible] strain, which will quickly dominate and are more infectious. And so those projections will need to be revised. As we see emergence of variants and potentially increased transmission as a result of them, Speaker 1: 05:11 Where does an increased vaccination program figure into this modeling? Speaker 2: 05:15 So vaccination will remove individuals from the susceptible pool and prevent and reduce the likelihood of them becoming infected. Therefore, reducing transmission overall, a vaccination program will both prevent infections as well as mortality. And that's good. And it also reduces the amount of circulating virus in the community, which will both reduce the, um, expansion of the [inaudible] variant and will also reduce the likelihood that there will be other variants that emerge that may be, uh, more infectious, more lethal, and the vaccines may be potentially less effective against them. So vaccination is a key strategy to reduce the amount of circulating virus and prevent the emergence of [inaudible] and other variants Speaker 1: 06:00 Could increase vaccinations, change the picture so much that we would not see a surge in any variant, and it wouldn't increase the number of cases. Speaker 2: 06:10 So our modeling has projected that a vaccination program can help flatten the curve, prevent infections and mitigate some of the expected surge that we anticipate due to the emergence of the [inaudible] variant and its increased transmissibility. It is likely that we will need more than just the vaccination program in order to continue this downward trend that we're recently seeing, observing in terms of case counts. The modeling indicates that even with a comprehensive vaccination program, we will still likely see cases at least returning to where they are now or potentially higher than we're currently seeing them. And so we need a combination of a robust vaccination program as well as strict adherence to masking and social distancing orders in order to reduce transmission and flatten that curve. Speaker 1: 07:02 Based on your research on the threats, variants pose, do you think the state lifting lockdown orders was premature? Speaker 2: 07:11 I think that we just need to be extremely cautious in the coming weeks and months to come and continually monitor the amount of viral transmission and be ready to act. If we see an increase in case counts and an increase in hospitalizations, one of the things that we can anticipate with the expansion of this B one, one seven variant is that we could see in a relatively short period of time on the order of weeks and quickly accelerating number of cases because of the expansion of the variants. I think we just need to be particularly, um, observant, cautious about reopening and able to monitor the situation and, uh, reverse policies. If we see concerning trends, Speaker 1: 07:57 I've been speaking with Natasha Martin, she is an associate professor in the division of infectious diseases and global public health at UC San Diego. Thank you very much for speaking with us. Speaker 2: 08:08 Thanks for having me. [inaudible].