Coronavirus latest updates in the Bay Area. Peninsula Doctor newsletter #13

Covid-19 Testing in the Bay Area

We’re now about three and a half months since the novel coronavirus pandemic began affecting our daily lives. Where’s the rewind button? As I’m sure most of you are aware, case numbers both locally and nationally have been increasing. We are now having higher numbers of daily new cases reported in San Mateo and Santa Clara Counties than we had during the peak in late March. Hospital numbers have remained low but have increased over the last two weeks. I’d like to reassure you, however, that local hospitals still have more than enough capacity to handle the need. While much remains the same as when I wrote our last letter, there has been some new research and reports, some of which I’ll address below.


We still have two types of tests available for the virus, the nasal swab to look for the virus itself, and a blood test to look for antibodies (which can show a past infection.) It looks like at some point we may have saliva-based tests that would be more comfortable than the nasal swab. As of now, however, all of the available laboratories are still doing nasal swab testing. Labs are currently taking longer to process the tests, given a recent increase in volume. We’re constantly looking at times at Stanford and Quest, and other sources, to try to provide the most accurate and fastest testing possible. Antibody tests are still available via blood draw here in our office, or ordered through Stanford. There have been articles recently in the popular press that report that antibody tests are ‘not useful.’ These reports surfaced after a Nature article described a falloff in antibody levels over time, and a Cochrane review showed that it takes a few weeks for antibodies to develop after infection. I still think that antibody testing can help us to know if someone may have had the illness in the past. While it has not been proven that having had the illness will create antibodies, nor necessarily be protective against getting the virus again in the future, experts still believe that having had the infection is very likely to result in at least short term immunity. In addition, I have seen no credible evidence that anyone has had a significant infection twice. Antibodies are also not the whole immune response. A recent article, not yet published, has reported on household contacts of known cases, who developed symptoms themselves, but did not develop an antibody. They showed that these people did, however, develop a cellular immune response, which is likely to be protective.

Risk factors

It has been known for some time that the main risk factors associated with significant COVID-19 infection are age and comorbidities such as diabetes, obesity, and heart disease. This has not changed. On the other side, with decreased risk, there are more reports coming out that children are both less likely to catch the virus, and less likely to have a severe case. In a study of households where someone had a confirmed infection, they showed that the ‘attack rate’ on other family members living there was age-dependent. They found that only 6.4% of those less than 20 years old also became infected. This compares to 18.5% of those 20-60 and 28% of those older than 60. Kids who do get the infection are also more likely be asymptomatic, have lower viral levels, and have lower antibody responses. Recent research in China, Italy, and with 23andMe has also shown that people with different blood types have different risks of getting the infection. Blood type A looks to be associated with a relative risk of about 1.2 to 1.45, and blood type O looks to be protective, with a relative risk of 0.65 to 0.86. This translates to about a 20 or 30% increase or decrease in risk. It is not known why this is the case, but it does look to be a real finding. We don’t routinely check blood type in patients, as there hasn’t been any medical utility in knowing it. They do, however, check it with blood donation, or sometimes before delivery (in pregnancy.) I’ve had a number of patients ask me if we know their blood type, and for most people we do not. We can, however, add this test on to someone’s next lab draw if they are curious about this issue. I don’t think it changes what most people would do, as it’s only a minor adjustment of risk.

Vaccine progress and treatment research

While there is much research happening in vaccine development, it will take some time before we have news on the progress. Vaccine trials are slow, and I suspect that we won’t have much more information until at least the fall.

With respect to medication treatment, there have been preliminary reports of success with the use of steroids (dexamethasone) in severe hospitalized cases. The benefit was only seen in people needing oxygen, and it’s not recommended to consider this treatment as an outpatient. I think the next exciting treatment option, going forward, will likely be a monoclonal antibody therapy. They are working at very specific medications to either treat the virus, or the immune system response. In addition, there are ongoing studies looking at using plasma from people who have recovered, to treat those who are having the acute illness. These treatments will likely still only be useful in the hospital setting. I do think that in the coming months, we will have better tools for our hospitals to use, that will help patients have better outcomes.

Transmission and prevention

It’s all about the mask! As much as most of us dislike wearing masks, it does seem that this is the key difference between halting virus transmission, and having continued spread of the virus. The data is becoming more and more clear on this issue. A Chinese study of 420 hospital workers with significant exposure to COVID-19 patients showed that not one of the protected hospital workers developed the infection. Outside of the hospital, a recent review in the Proceedings of the National Academy of Sciences looked at the case numbers in New York City versus the rest of the USA, Italy, and China. In the hard hit area of Lombardi, in Northern Italy, masks were made mandatory on April 6th. In New York City, masks became mandatory on April 17th. There was enough fear in NYC at the time, that people by and large were strict in following that order. In this study, they showed that the curve flattened significantly, and in time with, the strict use of masks. By contrast, the rest of the United States has been much more lax with the use of face masks, and we have continued to see a steady increase in case numbers. I think it is clear that airborne transmission is the dominant route of viral spread. A study done in Bonn, Germany, looked at household surfaces (door knobs, countertops, etc.) in households where at least one person had a confirmed case of COVID-19. They were only able to collect viral RNA from 3% of household surfaces, and were not able to grow the actual virus from any of those samples. While I’m not saying that we should abandon hand washing or wiping surfaces, I do think that our efforts are best spent in trying to avoid airborne transmission. Current guidelines continue to recommend that gatherings be as small as possible, preferably outdoors, and with at least 6 feet of distance. If we need to minimize a person’s risk, however, I feel that 6 feet of distance may not be adequate, even outdoors. This is especially true if the other person is not somebody already in your circle of close contacts, or who is talking forcibly, laughing, coughing, or sneezing. The risk increases if it’s for a prolonged period of time, such as at a dinner, or an event. While I understand that we all have our own level of risk tolerance, and that returning to more normal social activity has significant value, I also think that’s it’s useful to understand and consider what situations confer more or less risk.

I hope that this letter finds you and your family well, and staying safe. Thankfully, we are all fine here. I remain hopeful and confident that we will make it through this pandemic and look forward to a future where we can all be closer together, and more at ease. We are more than happy to hear from you by phone, email, or text, as well as see you in person. Please let us know if you have any questions or concerns.

Warmest wishes,
Ian Kroes M.D.

Coronavirus latest updates in the Bay Area. Peninsula Doctor newsletter #12


Coronavirus latest updates in the Bay Area. Peninsula Doctor newsletter #14


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