I am going to try a new brief format to help inform you about the Covid-19 epidemic that is disrupting all our lives. A question-and-answer (Q&A) approach may work well in this constantly changing environment when many topics may need updating.
Q1: What is the state of the epidemic?
A1: SARS-CoV-2 is not going away anytime soon. Infections in Massachusetts have crept up to high hundreds in the past week (from perhaps 300 daily), and national infections are over 40,000 daily and may be still rising. You have all seen the graphs. National deaths continue to accumulate at discouraging rates. Cold weather is likely to facilitate even more infections.
Q2: Where are the vaccines?
A2: Based on recent reports, experts (and I) believe we should have useful vaccines validated sometime in 2021 Q1. But their level of effectiveness is not yet known. Distribution and administration of vaccines may be able to start in 2021 Q2 or late Q1, but wide coverage is not likely to be achieved until 2021 Q3. Radically better availability can of course be hoped for, but seems unlikely according to multiple expert reports I have seen.
Q3: How effective will the Covid-19 vaccines be?
A3: The threshold for approval was set by the FDA at a 50% reduction in severity of disease, not even prevention of disease. For reference, the CDC notes that “flu vaccination reduces the risk of flu illness by between 40% and 60% among the overall population.” A few other vaccines are dramatically more effective, such as measles (97-98%) or polio (99-100%) vaccines (CDC). Dr. Fauci of CDC “hopes” for a Covid-19 vaccine with 70% effectiveness, but no one yet has clinical data to measure effectiveness.
Q4: How much difference will a C-19 vaccine make?
A4: A moderately effective vaccine with 60-70% efficacy will help to slow the spread of SARS-CoV-2 in the community, but an individual will still have a 30-40% chance of catching Covid-19 disease upon exposure. So close contacts indoors and similar activities will still be risky; your safety behavior is not likely to change much, though apprehension could be reduced. A highly effective vaccine (over 90%, like the new shingles vaccine, as well as the measles or polio vaccines) should provide enough individual protection to allow more normal socializing.
Q5: Is hospital treatment of Covid-19 better?
A5: For seriously ill people, the use of remdesivir and steroids has reduced ICU stays and improved outcomes. The monoclonal antibodies used on the president remain unproven, with only a handful of people actually having been administered them. They may prove to be helpful but we really need data, as we do for convalescent antibodies from survivors of the infection, which likely are helpful but for which the benefit and timing are not fully substantiated. Overall, hospital death rates are much lower than in the spring, but still substantial. Covid-19 death rates are dramatically higher than those from seasonal influenza, probably by a factor of 10.
Q6: Is there outpatient or preventive therapy for Covid-19?
A6: No, we have no proven preventive or outpatient therapy for the Covid-19. Hydroxychloroquine doesn’t work. There is no breakthrough publicly in the works.
Q7: If I get sick, what do I do?
A7: After relevant symptoms and a confirmed test, you isolate yourself at home, take your temperature and oxygen saturation daily, and take it easy. We will talk to you daily and give advice. The duration of symptoms is frequently 10-14 days, for mild cases. Asymptomatic disease discovered through contact tracing is also well known. If you worsen, we will direct you to hospital.
Q8: How long do I need to isolate myself after infection?
A8: CDC says you must isolate yourself for 10 days after initial symptoms in a mild infection, or the date of a positive test for asymptomatic people. For moderate to severe infections (manifest by hospitalization, need for oxygen, need for aggressive therapy such as steroids or remdesivir), the CDC recommends longer isolation, specifically 15-20 days. The purpose of isolation is to prevent your giving the disease to close contacts during the recovery phase. The president did not follow CDC isolation guidelines.
Q9: Can viral testing be used to shorten isolation?
A9: The significance of viral testing during recovery is not fully clear. Even PCR tests are imperfect with known false-negatives. And viral fragments can persist in the nose and nasopharynx that induce positive tests in the absence of true infectivity (measured by culturing live virus from the samples). The CDC guidelines for isolation are practical experience-based recommendations for protecting other people after your infection.
Q10: Am I immune after a C-19 infection?
A10: You likely are immune for at least 3 months following an infection. We do not have much data on the duration of immunity nor on its reliability. There are now reported cases of clear repeat infections. This is a nasty and formidable virus. If you were infected, consider donating serum for the convalescent antibody research.
Q11: Any quick updates on virus transmission?
A11: Yes. Respiratory droplets from talking, singing or coughing remain the major path of transmission. Distancing by 6 feet or more is helpful to block this. But aerosol transmission, meaning finer virus-carrying mist which can float, persist in the air, and move widely within an indoor closed space, has been clearly implicated as well. Surface transmission appears to play a minor role (and should be blocked by good hand hygiene). So little worry about your mail or groceries. Children can definitely be infected and spread the disease to adults even if without symptoms.
Brief summary: Plus ça change
This is our life for the next six months, almost for sure: You must continue to wear a mask whenever in contact with others, continue to socially distance (at least 6 feet) even when you have a mask on, and wash your hands (or use sanitizer) frequently. Outdoor activities can be done without a mask if you are truly separated from others, otherwise a mask remains necessary for everyone’s protection. All indoor events carry risk of infection despite masks and separation.