Antibodies Vaccine Variant

Bad news about the circulating variants…

If you remember, the South Africa variant (better known as 501v2), Brazil variant (better known as B1.1.28/501.V3), and the UK variant (better known as B1.1.7/501Y.V1) have all recently grabbed the attention of scientists because each have mutations on the spike protein. These are important to investigate because the spike is the keys to our cells. In other words, the virus can mutate to make a smarter key.

There are two new pieces of information this week/today.

First, the 501v2 (South Africa) variant…

-What happened? On Jan 20, a preprint came out from Rockefeller University. They took the antibodies of 20 volunteers who received an mRNA vaccine and mixed it with viruses containing the mutations. This experiment, called an antibody neutralization assay, enables the researchers to determine whether vaccine-induced antibodies will be effective against the new variants of virus circulating globally.

-What did they find? The antibodies effectiveness against the mutations was reduced by a small (but statistically significant) degree (ranged from a 1- to 3-fold reduction).

-What does this mean? The vaccine is working against 501v2 (thanks to the polyclonal response), but these mutations *may* impact the efficacy of the vaccine. We need more “real-world” studies, in addition to the well-controlled, test-tube studies.

Second, the B.1.1.7 (UK) variant…

-What happened? Today, NERVTAG (New and Emerging Respiratory Virus Threats Advisory Group) met to discuss new studies on B.1.1.7. They previously reported a study in which there was no increase in death due to the new variant. However, with more time comes more data.

-What did they report? There are three new studies (one by The London School of Hygiene & Tropical Medicine, one by Imperial College London, and one by University of Exeter) that all showed that the B.1.1.7 is more deadly by about 1.65 fold.

-What does this mean? “There is a realistic possibility that B.1.1.7 is associated with an increased risk of death compared to the virus without these mutations.” While the risk of death remains low, this does increase it by a significant amount. There is a limitation to these studies… Only 10% of COVID19 deaths have their virus coded to know which mutation the person had. In other words, this could be a bias sample. Deaths are lagged from cases, so the more time goes by, the more and more accurate of a picture we will get.

Bottom line: The virus is getting smarter. Slowly but surely. This underscores the need to vaccinate as many people as quickly as we can, because these mutations are signals of antigenic drift.

Love, YLE

Data Sources:

Rockefeller study:…/2021.01.15.426911v1.full.pdf

NERVTAG meeting minutes:…/NERVTAG…

I knew the SA story was coming out at some point this week, so I prepared with two brilliant colleagues, Dr. Jessica Steier (public health scientist) and Dr. Andrea Love (immunologist). They are both doing wonderful work at The Unbiased Science Podcast (

Antibodies Vaccine


I’m getting flooded with messages and questions! Which is fantastic, but I do this in my “free” time and can’t possibly get back to each and every one of you. Here is my attempt to answer a lot of your questions all at once…

Antibody test after vaccination…

Do not get an antibody test after your vaccine. The vaccine gives your body instructions on how to make specific antibodies to fight the virus. These are not necessarily the same antibodies that antibody tests look for. So your test may be negative, but this is not indicative that the vaccine is not working.

“Natural” vs “vaccine” antibodies…

The physical antibody you get from either are exactly the same. The difference, though, is the strength of your response. There could be a difference in your immune response if you got “naturally” infected compared to vaccinated. Research shows that “natural” antibodies do fade off among 10-15% of people. The only way we could actually know this is if we tested your antibodies every day, and we aren’t going to do that. We know that vaccination provides the perfect formula (this is the purpose of Phase I and II trials).

Delaying first dose to ensure second dose…

Do not do this. Get your first shot if you are eligible and can get an appointment. Odds are, you will get your second dose on time. If not, immunology tells us that the vaccine doesn’t require the precision of a couple days or even a week. Beyond that, we don’t know. But don’t delay a high probability event (getting a vaccine and it working) with a low probability event (getting a delayed second dose and it not working).

Autoimmune diseases and the vaccine…

The CDC states that people with autoimmune conditions may receive an mRNA vaccine. However, there is no data currently available on the safety of mRNA COVID-19 vaccines for you. Individuals from this group were eligible for enrollment in clinical trials. Talk to your healthcare provider.

Immunocompromised and the vaccine….

The CDC states that people with HIV and those with weakened immune systems may receive a COVID-19 vaccine. However, they should be aware of the limited safety data:

* Information about the safety of mRNA COVID-19 vaccines for people who have weakened immune systems in this group is not yet available.

* People living with HIV were included in clinical trials, though safety data specific to this group are not yet available at this time.

People with weakened immune systems should also be aware of the potential for reduced immune responses to the vaccine, as well as the need to continue following all current guidance to protect themselves against COVID19. Talk to your healthcare provider.

Medical advice…

I cannot give medical advice. I’m not qualified. And, even if I were, I don’t know your medical history. Please talk to your healthcare provider about side effects, about whether you should get the vaccine, about symptoms, about your history of allergies, etc. And if they aren’t willing to talk to you about the vaccine, please find another provider.

The CDC website actually has some fantastic information. But it is difficult to navigate, I get it. I’m certainly not going to compete with the CDC, but you can also always use the search function on my blog. Just throw in a word on the topic you’re interested in, and the science should pop up. I also “tag” my posts with “themes”. So, for example, you can select “children” on the list of categories and all my posts with that tag will show up.

Love, YLE

Data sources:…/recomm…/underlying-conditions.html…/2019-ncov/vaccines/facts.html

Antibodies Vaccine

Vaccine after COVID19 infection

If you’ve previously had COVID19, you still need the vaccine.

Let me repeat for the back to hear.

If you’ve previously had COVID19, you still need the vaccine. Even if you had a positive antibody test.

Studies have shown that ~10% of people who recovered from COVID19 have weak antibodies and they wean off after a while (it looks like about 90 days). When the antibodies wean off, you will get reinfected if you come in contact with the virus again. And you won’t have protection. (By the way, this is what’s causing the small rate of reinfections).

Unfortunately, we can’t accurately predict who those 10% of people are. The only thing we know is that typically mild infections don’t mount a strong or lasting immunity to the virus. The worse the first infection, the stronger the immune response will be.

So, because we don’t know whether you land in the 10% category, everyone needs a vaccine. Vaccines provide you with the “perfect formula” needed to have a strong antibody response so the virus doesn’t overwhelm your body. Everyone will be on the same playing field.

Strong “natural antibodies” (ie not from a vaccine) have shown to last up to 8 months. But that’s because these studies were only 8 months long. As I’ve mentioned many times before, we are expecting antibodies to last 1-2 years because that’s how long COVID’s cousins last (SARS & MERS). Not enough time has passed to know for sure. Also, we won’t know how long immunity produced by vaccination lasts until we have more data on how well the vaccines work. There no reason to believe, though, that “vaccine antibodies” act differently than strong “natural antibodies”.

If you currently have COVID19, you CAN wait up to 90 days for your vaccine. That’s because reinfection is incredibly rare before 90 days. But you CAN get it sooner. Pfizer clinical trials included people who did or did not have COVID-19 previously and some people got the virus during the study. These situations did not present any issues of concern. If you currently have active symptoms of COVID-19, the CDC recommends you wait to get vaccinated until you’ve recovered and met the criteria for ending isolation:

  • At least 10 days have passed since symptom onset AND
  • At least 24 hours have passed since resolution of fever without the use of fever-reducing medications AND
  • Other symptoms have improved.
  • And that’s mainly because we don’t want you infecting other people when you go get your vaccine.

Love, YLE

Data Source:
~10%: ; ;
Ending home isolation:
How long antibodies last:


COVID19 antibodies… (Part 2)

There are, understandably, still a lot of questions after my last post; the immune system is complex. AND scientists still have a lot of unanswered questions themselves, which is likely adding to the confusion.

Three additional noteworthy points…


Antibodies are primarily intended to prevent disease (i.e. symptoms and illness). They do NOT necessarily protect against infection. In other words, you can have COVID19 antibodies AND harbor the virus (and thus continue to spread the disease to other people months after you recover). We do not know yet if COVID19 antibodies induce sterilizing immunity. Sterilizing immunity means that the immune system is able to stop COVID19 from replicating within your body.


Not all vaccines produce sterilizing immunity, but they don’t need to in order to be effective at preventing disease (i.e. symptoms and illness). For example, the polio vaccine does not induce a sterilizing immune response but is still 90% effective in preventing disease (i.e. symptoms and illness). On the other hand, the HPV vaccine does induce sterilizing antibodies. COVID19 vaccines MAY provide sterilizing immunity. We are seeing things called neutralizing antibodies in the data. However, scientists are not convinced yet.


There are cases of COVID19 reinfection. We expect this from our understanding of other viruses. However, COVID19 reinfection is rare. If you get COVID19 disease (i.e. symptoms and illness) months after an initial infection there are three possibilities: 1) You could truly be reinfected (i.e. you didn’t produce antibodies in the first place); 2) it’s a lab error/false positive (this is also rare); or, 3) you have a slow viral shedding rate (some people take months to get rid of the virus). If you feel like you’ve been reinfected, inform your local health department. There are protocols in place to report reinfection so we can investigate and study these cases more closely.


If you have antibodies or had a previous infection, you STILL need to wear a mask and socially distance and wash hands and everything else. At least until we understand this complex system a bit better (or a vaccine comes and everyone has had a chance to get it).

Love, YLE


COVID19 antibodies

Lots of questions coming in about this.

COVID19 antibodies are acting as we predicted…they are lasting long. In the beginning of the pandemic, we hypothesized that they would last 1-2 years like its cousins (SARS and MERS). So far, COVID19 is on track with this timeline.

Until now, studies have shown that COVID19 antibodies last 3 months. But that’s because these studies were only 3 months long. We were (and are) at the mercy of time.

Now that more time has passed, longer studies are coming out. Recently, three separate publications have shown COVID19 antibodies last 120 days, 155 days, and 240 days (8 months). In other words, the majority of people that recover from COVID19 have enough immune cells to fight the virus and prevent illness for at least 8 months. Again, these studies were only 120, 155, and 240 days long, respectfully. Antibodies likely last even longer.

The antibodies have a slow rate of decline. Two important points regarding this…

  1. You shouldn’t worry about waning COVID19 antibodies. This is normal a normal sign of a healthy immune response. It doesn’t mean these people are no longer protected. Antibodies only represent one part of the immune response; it’s not the full picture.  
  2. The slow decline suggests that the antibodies could last a very long time. This wouldn’t, necessarily, be surprising because we know that SARS (COVID19’s cousin) immune cells can last up to 17 years after recovery.

Frequency of Vaccines. Once we have a better picture of how long antibodies last, we can determine how often we will need a vaccine. This has yet to be determined.

Mutations. There have been COVID19 mutations. However, these mutations haven’t changed the virus enough to impact a vaccine effectiveness. We are keeping a close eye on this, though, as this is always a possibility with a virus. This is why a lot of scientists were/are paying attention to the mink mutation in Denmark.  

Love, YLE

Data Sources…

“Long term” antibody studies: (122 days), (115 days), (8 months)

3-month antibody studies:


Antibodies Drug treatments Innovative Solutions

Plasma and COVID-19

What is plasma? When people get sick, immune systems generate antibodies to fight the disease. Those antibodies (especially among very sick patients) float in people’s blood plasma — the liquid component of blood. 

How can it be used? Plasma from a recovered person (who was very sick) can be injected into a currently sick person. The antibodies fight the virus early until the patient’s own immune system has enough to fight. Plasma has been used to fight epidemics, like the 1918 Spanish Flu, diphtheria epidemic in the 1920s, and the Ebola outbreak in 2014.

Plasma to fight COVID19? This has slowly come to the surface in the 2020. Here’s a timeline…

January 20-March 25: China treated 5 COVID19 patients with plasma. It worked.

March 24: FDA issued guidelines for using plasma in emergency investigations of new drug protocols (called eIND)

March 31: COVID19 plasma was used for the first time in the U.S. (Houston Methodist). It worked (for the most part).

May 14: A meta-analysis was published. Only 8 plasma studies had been conducted thus far and they were mainly “case studies” (basically a story with what happened with a few patients). There were no randomized control trials (RCT). The conclusion? We have no idea if plasma works because we don’t have enough evidence.

July 10: An updated meta-analysis was published pooling all studies on plasma. There were 20 published studies by now, but only 1 RCT. Their conclusion? We have no idea if plasma works because we don’t have enough evidence.

August 13: Mayo Clinic released a study with over 35,000 patients. They found that plasma helped with patient outcomes (like less death). BUT this was not peer-reviewed, which is important because this study has some serious limitations. Most importantly, there was no placebo group. The specific role of plasma is unclear because all patients received at least one additional medicine at the same time. This makes it difficult to know whether it was the plasma or the drug that helped the patients.

August 23: Nonetheless, the FDA allowed emergency authorization for doctors to treat Covid-19 using plasma

August 25: Three randomized control trials had concluded (one in China, Netherlands, and Iraq). The Chinese study was stopped early because they couldn’t get enough people to enroll. The Netherlands study was stopped early because most of the participants already had antibodies. The Iraq study was too small to see whether plasma helped.

Today: From my count, there are 98 ongoing studies evaluating plasma, of which 50 are randomized. We don’t have the results of these studies yet.

But… if it’s worked for other pandemics, why not just use plasma for everyone? Safety. 14 of the current 20 studies have reported serious adverse events with plasma. In one study, scientists reported that 4 deaths were directly linked to plasma infusion (out of 15 deaths total). It’s important we get this science right.

So, now what? We wait. We NEED rigorous studies to conclude. These are very difficult to conduct, though, because we need enough people to donate plasma AND we need enough people to agree to be infused. But, thanks to the perseverance of many scientists and brave community members, results should be coming out soon. TBD.

Love, YLE

First plasma treatment in China:

May study:

July study:

Mayo clinic study:

FDA August announcement:

Antibodies Children GA Innovative Solutions National changes Social Distancing


Buckle up. In true 2020 fashion, several scientific developments popped up while I was on vacation…

1. Teachers’ and parents’ risk for severe COVID19

• 2.95 million teachers (50.6%) have risk factors for severe COVID19. This is mostly driven by obesity or heart conditions

• 37.7 million adults living with school-aged children (54%) have risk factors for severe COVID19. This is mostly driven by age, heart problems, or diabetes

• Risk is the same for those living with younger children compared to older children.

• So… what? “Without adequate safeguards, reopening schools could put millions of vulnerable adults at risk for severe COVID-19 illness”.

2. First global case of COVID19 re-infection

• In March, a 33-year-old man in Hong Kong was infected with COVID19. He had mild symptoms.

• Last week, he was infected with a different COVID19 strain and tested positive upon his arrival to Hong Kong from Spain. He is asymptomatic.


• After the first infection, he had no antibodies. But we already know that not everyone gets antibodies (especially mild symptoms; see my previous posts)

• After the second infection, he did produce antibodies. This is consistent with the immune system building stronger with each exposure to a pathogen, so second and third exposures may increase the chances to develop antibodies.

• In the words of immunologist Dr. Akiko Iwasaki, “This is no cause for alarm – this is a textbook example of how immunity should work.”

• Vaccination (and social distancing and masking) needs to be considered among people that have already been infected with COVID19

3. Wearing masks works (I feel like this is no duh, but in case you needed more ammunition)

• US states with high mask wearing compliance were more likely to have a R(t) less than 1 (control of community transmission)

• Mask wearing was higher among women, elderly, non-white or Hispanic, lower income people

• Mask wearing is highest along the coasts, southern border, and urban areas (see Figure)

• Mask wearing is even more important when (or if) social distancing is relaxed

4. Super-spreaders played a key role in MERS and Ebola. Their role in COVID19 was just revealed in Georgia:

• 2% of the population is responsible for 20% of infections• Super-spreaders likely explain major outbreaks in rural areas • Younger people are more likely to be super-spreaders

Love, YLE






Antibodies and Reinfection

What we know so far (previous posts, with of course the scientific studies, are linked at the bottom):

• Antibodies develop following the majority of COVID19 infections (yes among both symptomatic and asymptomatic cases) • Antibodies are detectable by 19 days of symptom onset • Antibodies last at least 3 months. Which is fantastic news, because these studies were only three months long

What we don’t know so far: • How long antibodies “truly” last. Unfortunately, this just takes time. If COVID19 antibodies are anything like its cousins (SERS and MERS), we would expect 2-3 years. • How well the antibodies protect us from reinfection.

Well, a new study gives us a glimpse on our second unknown: antibody protection from reinfection

What happened?

May 18-19: Before leaving for sea, all 122 crew members (113 men and 9 women) were tested for COVID19 and COVID19 antibodies. No one tested positive for an active COVID19 infection. 3 crew members tested positive for antibodies.

May 20: The fishing vessel left for sea from Seattle, Washington

June 5: Ship comes back because one person has symptoms (then tested positive and then was hospitalized). Everyone else was tested too and followed up for an average of 35 days.

June 12: By this date, 98 crew members tested positive

June 22: By this date, another 3 crew members tested positive

By end of study: 104 crew members (85.2% attack rate) tested positive for COVID19. 0 of the 3 crew members that had antibodies prior to departure tested positive for active COVID19 infection nor did they have any symptoms.

Translation? In this case study, antibodies are associated with protection against re-infection from a slightly different strain. This is great news, especially when we are working desperately and tirelessly for vaccines.

Love, YLE

Data Source:

Previous post: How long do antibodies last?

Previous post: “Natural herd immunity” and antibodies:

Picture: This is an actual picture of the fishing vessel thanks to Michael Brunk/

Antibodies Herd immunity Innovative Solutions Long-term effects


Never thought my physiology degree would be worth anything. But here we are!

Our immune system has special types of cells with different functions: 1) B-cells (antibodies) latch on to the virus so they can’t enter the cells; 2) T-cells find and destroy the virus (and then remember who they need to destroy). T-cells have been found effective in MERS and SARS, but their role in COVID19 has not been clear.

One study in Singapore was just published on COVID19 t-cells. Briefly, they found:
• T-cell response is high among mild COVID19 cases (unlike the antibody studies we have seen)
• Interestingly, healthy people have COVID19 t-cells. This be due to exposure to other related coronaviruses, such as the common cold and SARS. This MAY explain why some people control the infection (and recover much better) than others.
• T-cells lasted over 17 years among SARS survivors, and the SARS t-cells WORK against COVID19

So far, all vaccines being developed target B-cells (antibodies), but scientists are starting to explore the potential of leveraging T-cells for therapeutic options. The problem is t-cells are much more complicated to analyze compared to antibodies. If fact, they require a special laboratory. So, we can’t do large population-based studies like we saw in Spain (

To my knowledge, there are only three other published studies on this topic (regarding COVID19). I’ve included them below.

Love, your local epidemiologist

• Diao et al, 2020.
• Grifoni et al, 2020.
• Weiskopf et al, 2020.
•Le Bert et al., 2020 (Singapore study):…/s41586-020-2550-z_reference.pdf

Antibodies Long-term effects

How long do antibodies last?

Over the weekend, a study was released on the longevity of COVID19 antibodies in New York. This is important in regards to the effectiveness of vaccines.

This new study just focused on symptomatic and confirmed COVID19 cases. Bottom line? Antibodies were found to last at LEAST 3 months (the study was only 3 months long). More details: Scientists followed 19,763 hospital employees who tested positive for COVID19. After 52 days of symptom onset, the scientists took a blood draw to test how many antibodies people had: 7% made low levels of antibodies; 22% made medium; and 70% made high levels of antibodies. Then the scientists took a blood draw 82 days after symptom onset. Antibody counts were relatively stable. Only one person had zero antibodies.

This study both compliments and contradicts a smaller study conducted in China (Long et al., I posted earlier). Their bottom line? Antibodies lasted at least 8 weeks, but not for everyone. More details: Among symptomatic patients, 84% had antibodies during the first follow-up and, of those, 87% had stable antibodies at the second follow-up.

So which study is “correct”? The NY authors state that the discrepancy between studies is likely due to evaluating different types of antibodies. ALSO it typically takes hundreds (if not thousands) of studies to clearly see the full story. Replication among different populations is key to make generalizations. However, the first few studies gives us an initial peak into biological mechanisms.

So we know that the antibodies fights off re-infection among primates and we know that transferring plasma among humans also reduces virus replication. We also know that antibodies from other coronaviruses (like MERS and SERS) last 2-3 years. This NY study will continue to collect information on the employees to continue to track antibody responses over time. I look forward to seeing their follow-up results.

Love, your local epidemiologist 

Data sources: Figures by me using data from the following two studies:
Wajnberg et al., SARS-CoV-2 infection induces robust, neutralizing antibody responses that are 2 stable for at least three month. 2020; Q. X. Long et al., Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections. Nat Med, (2020).